Don't worry about the crying, those little *******s cry all the time. What you should really do is mix some vodka or extra-strenth nyquil into their milk. Knocks those little ****-machines out for hours, so you can actually get some sleep at night.
Have you had her checked for thrush in the mouth? This can cause pain while feeding. Also, you could be on the right track about the ear infections. I have had a few ear infections this year, and if drinking from a bottle of water, it does hurt. The pain is very very sharp and searing, and even causes me to cry out sometimes.
Have you tried giving babys' painkiller, like Calpol? If this continues, please see a doctor or health professional. Feeding times can be a lovely time, its a shame if its causing upset for you both