S.,
It sounds exactly like my 4 year old when he was born - he sounded so weird, it really freaked people out. He was diagnosed with tracheomalacia, which means that his trachea wasn't fully formed/hardened when he was born, so it vibrated a little when he breathed. Sometimes he sounded like a goose honking! He also had reflux, which I think either exacerbated or was exacerbated by the tracheomalacia. Both he outgrew by about 18 months.
I agree with one of the other posters - give the medicine a chance. We started on Zantac but ended up switching to Prevacid - it was a pink powder that we mixed with water and gave with a dropper - he loved it.
Another thing you didn't mention trying was small meals - very important! I think we did 2 or 3 ounces at a time, at the most. I actually had to switch from breastfeeding directly to expressing and giving with a bottle b/c it just seemed to work for him much better.
Make sure he doesn't lay down for at least 30 minutes after a meal. Also, our ped said he should sleep on him tummy, which I know is normally a no-no, but better than on the back in our case.
That's all I can think of right now - seems like ancient history as I try to remember everything. Best of luck and contact me directly if you want to chat about it more!
K.