The best medicine to help your nipples heal is your milk itself. After each feeding and off and on throughout the day, express a little milk and rub it completely around the dark portion of the nipples. (The actual name for this part of the anatomy escapes me at the moment; I had a horrible migraine that landed me in the ER this past weekend so I was out of it most of the week after an injection of Dilaudid and Phenergan). This should help with the soreness as well as the healing. Do this especially after each feeling.
Make certain when your baby is latching on, that he is doing so correctly. Be certain he is taking the entire brown portion of the nipple into his mouth. If he isn't, then press your pinky finger between his mouth and your nipple to sort of "pop" the seal. If you take him off otherwise, it will cause soreness, pain, and even bleeding, plus the baby will be none too pleased at being taken off the breast once he gets going.
Are you sure you're not engorged? If your milk production is too high and your breasts too full, it will be difficult for the baby to latch on. If this happens, run a tub of warm to hot water but not too hot in order to allow your milk to let down. Once the water warms, have someone bring you the baby or have him in the bassinet so you can take him into the tub with you so you can nurse him there. I called Le Leche League (they are online by the way, and you can call and/or email them. If you need answers quickly, please call them! They are the best resource I found when I needed help in the early days and throughout the tough times when I was nursing and I did so for about 10 months until my daughter basically weaned herself to a cup.)
The La Leche League's International Web Address is http://www.llli.org/. Just find the country, state, area that is local to you and you should be able to locate a toll free number. Even if it's not a toll-free call these days, their help and answers are well worth the cost of the call. I learned so much from the phone calls and received much-needed support. Breast-feeding was not a big thing around here where I live until, or so it seemed, I began breast-feeding my daughter even when we were out in public. Of course I covered up well and often, especially when she was newborn to about 6mos, she was in a baby-sling that an elderly woman made for me. It doubled when she was older as a sort of side pack then a back-pack almost like a papoose sack that either my great-great-grandmother (Arapaho Indian) or the other great-great-grandmother (Cherokee) would have used when carrying their children around. My maternal great-grandfather was full Cherokee and took an Arapaho bride. Being that my birth father's family are primarily Cherokee with the exception of 2 brothers who came over from Ireland back in the 1600s then married Cherokee wives, my family is mostly Native American. It came in handy when having both my children. I had access to items the elderly women made that they used when their children were small that most mothers don't have access too b/c the commercial retail industry simply doesn't know of these products or can't make enough money off them or probably most of all, they would rather make something so cheap it would put the child in danger rather than something that can pass from one generation to the next or last through multiple children.... that's just my opinion. Others' opinions may vary...
Give La Leche League a call. A breast-feeding counselor can give you a great deal of information that may help your doctor figure out what is wrong.
BTW, when you are home, I presume you are a SAHM right now, go without your bra as often as possible. The likely culprit of the yeast is having your breasts bound up in an ill-fitting, non-breast-feeding style bra that is not made from cotton so it cannot breath and therefore it is breeding bacteria instead. When I had to wear bras, I had the lady from Sears fit me with cotton nursing bras that had clasps that were easily undone and done back again through shirts that were also fitted for nursing through. I also had cotton pads I wore to protect against leakage when my supply was heavy and I had to go out. When home, I generally went bra-less as often as possible. I wore a fancied strapless bra cut down with extra cotton padding that I could wash in the sanitary cycle in a laundering bag for undies, bras, and lingerie. I washed everything in that baby brand of detergent... the name escapes me but it makes everything softer too. It also has a great cleaning agent in it. I have a set of HE washer/dryer with the risers in a front-loader set. It's an HE3T Kenmore. It has a sanitary cycle and the machine includes an independent heater that heats the water to the correct degree to ensure anything run through that specific cycle comes out sanitary. I washed the one pacifier my daughters would take through the dishwasher under a similar sanitary cycle as our dishwasher also has that extra built-in heater to heat the water to a higher temperature than the hot water heater does.
Again, air to your breasts and rubbing a few drops of your bodies milk on the nipples does a great job in healing. Try your hand at making the make-shift strapless bra. It's not as if you will wear it outside your home. I couldn't see to sew a stitch and had given away my electric sewing machine by that time so I had a time making a straight stitch but the end result turned out quite well. I sewed in a couple of the rewashable pad inserts for your bras when nursing or after the birth of a baby to help absorb any extra milk flow. It worked wonders to help because the braline was always below the nipple line allowing me to wear extra-large airy shirts to let the air in and stop the binding and growth of bacteria. It helped me lots; perhaps it can help you too.
One more thing, I used the pump one time then learned I could express milk by hand much faster and with less pain than with a pump. Once I did this, I NEVER used the pump again. I recall the pump making my breasts hurt like mad. It felt like both were bruised beyond belief like someone had pulled all the blood to the surface like a big bruise or something. Expressing by hand never did this. There is an area that I always refer to as the "sweet spot" where if you start there, then sort of press and pull the milk will flow like a faucet. Maybe it was the years I spent living on a farm where I milked not only cows but goats as well. Believe or not but I actually brought home a bobcat who was pregnant and my mother and birth father nearly went into fits! They let me keep her at home until she delivered but she ended up delivering more kits than she could nurse. She had 15 kits in total. She could only nurse 8. We took turns alternating out nursing the kits so each could receive milk from their mom while the others received a milk mixture our vet helped us come up with for the kits so they could grow. Eventually, I was able to teach the mother to teach the kits to hunt and with the help of a wildlife worker who was rather upset with me but ultimately realized I knew what I was doing and in the end I did a good thing, we were able to reintroduce the family back into the wild. I also ended up with a raccoon too... Everyone whose ever known me, especially my birth mother and my surrogate mother (her oldest sister who was more like a mother for me) always said any stray within a 100 mile radius would find its way to my house, especially if it were hurt, hungry, or pregnant. LOL! I've took them all in. The raccoon was actually brought to me by a cousin after the baby's mother was accidentally killed in a trash compacter at a company near where she worked. She didn't know what to do and didn't want to turn the animal over to the wildlife group so she brought the baby raccoon to me and I raised it. Sam lived a long, healthy, happy, and fun-filled life. Even today I still have strays. My cat is from an animal shelter although he's on up in age now. I lost a manic Quaker parrot who was upwards of 50 years old about 2 years ago. It took me about 6 months before she would let me handle her without wanting to rip me to shreds. I wore gloves to start with then I was able to handle her with bare hands. Eventually she even allowed my youngest daughter to handle her and her major fear was of small children b/c the home she was saved from had 6 children all under the age of 11 who tortured her constantly. She was loud, nearly bald, looked horrible, her beak was in terrible shape, and her toenails were even worse. Plus, she was on a seed diet vs appropriate pellets, fresh veggies, oatmeal (with cinnamon - they LOVE cinnamon!), and plenty of fresh water with other treats offered plus playtime EVERY day several times a day. She was fortunate to have lived as long as she did considering the shape she was in when she came to me. She shrieked all day and all night long. Once she began accustom to someone talking to her, she quieted down and began to actually talk in words then in sentences. Nobody ever thought she'd learn to talk as old as she was but she did. I miss her terribly. This has been my life in addition to taking care of horses, dogs (I have had two guide dogs and my second is currently in partial retirement due to old age), cats, parrots, various types of birds including pigeons and finches, ferrets, cows, pigs (pet pot-bellies and the farm variety), etc... I've helped deliver babies too including a set of twin goats, which I had never heard of but looked up as an adult and learned it wasn't as uncommon as I first believed it to be. I've helped with a c-section on a foal (horse) as well as a few natural births including turning one with the help of the vet in order to get the baby in P. to be born safely without losing both the mare and the foal. I've taken care of kittens abandoned by their mothers who refused to allow them to nurse & even taught one first-time mother cat and a first-time mother dog how to lay still to let their litters nurse. other times I've fed them myself with special-made bottles. I've hand-fed a few baby cockatoos too when helping out a friend who owned a pet store. But I digress...
It's a good thing I've always been an excellent researcher and had no qualms with calling companies or other sources for answers. That's sort of how I approached La Leche League. I had something important my daughter needed yet we were having problems that the local pediatrician, lactation counselor, and ob/gyn could not handle so I took it up a few pegs and gave them a try. They found the answers I needed to make it not only a wonderful experience but a successful one. My first child was unable to be breast-fed because of a discharge I was having that somehow make my breast-milk unhealthy for her; this child was sick throughout her entire childhood no matter how well I fed her as far as diet, clothed her, bundled her, etc... nothing worked. She stayed sick; however, with my youngest child who was breast-fed, she was only sick once a year, if that, from the time she was born right up until she was several years old. Once she began school of course she caught the occasional cold but still, she never had illnesses like her older sister, which I am forever thankful. At least one of them spent a childhood without always being sick.
Best of luck... and please forgive my rambling. I'm still on migraine meds which are making me a bit loopy at the moment. It's an attempt to prevent the former migraine from rebounding again. So far - so good. Wish me luck too.
Warmest regards and all my blessings...
Paise