Like PP's said, call a lactation consultant or your local La Leche League. Here's a link to the page for the Lodi group:
http://lllnorcal.org/groups/LodiCA.html
Call one of the leaders and get her advice.
They are having their monthly meeting next Tuesday, the 21st, so I'd highly recommend going! It's a great opportunity to get feedback and help from moms who have been there, done that. You don't need to be a member to come to meetings and there's no pressure to join - their goal is just to support you in your breastfeeding journey.
In the meantime, you might want to try going one-sided for a couple of days (or if not going completely one sided you could decrease the time he spends on the painful breast) so that your nipple has a chance to heal up. If you can continue to pump that side it would be best b/c that way you'll continue to make plenty of milk and won't be risking plugged ducts or mastitis. Your one breast will quickly adjust and make plenty of milk for your LO to drink if you just let him nurse whenever he wants to.
But I'd see a lactation consultant or La Leche League leader before I'd follow the advice of someone online. :)
Good luck!