K.W.
You probably know this, but there is actually something different about the suck/swallow mechanism with breast vs bottle, and if you're little peanut is battling an ear infection nursing him is much better. Also, the breastmilk itself can clear an ear infection. If I were you I wouldn't waste the time & energy to go to the doctor... ear infections usually clear themselves, and antibiotics are no longer recommended to treat them (in most cases). So, you're more likely to pick up some other type of illnes at the pediatricians office than you are to find a solution to your current problem! I've never had twins, but I would suggest trying to exclusively nurse the baby with symptoms until he is ready to take the bottle again. Of course by this time, your other baby is probably symptomatic. The most important thing as with any illness, is hydration, so you might have to get creative. One of my favorites is one of those sucky sock things with an ice cube in it.
Good luck!
K. (Nurse turned full-time mom of 2)