Sometimes, when I read breastfeeding tips and advice, I feel like it's all aimed at a more "normal-sized" woman. Hold the baby in close to nurse, make sure baby's body is flush with yours. Bah. That may work for a woman with a C cup, but that never worked for me. It took me a while to become comfortable enough with nursing to play around with positioning, but once I did, it made all the difference!
If you're a larger woman like me (with my first, I was an I cup; I'm currently an H-I, depending on band size), the angle that our nipples go into the baby's mouth is different than the angle a smaller woman's nipple goes into her baby's mouth. And angles can mean all the difference between having discomfort/pain and not. If you are larger and find that you're having pain but the baby seems to be latching on correctly, and there's no sign of the baby being tongue-tied, start playing around with positions! Make sure you have lots of pillows around to support your baby, and start shifting the baby around. It doesn't have to be a lot; even just a centimeter can change the angle enough to give you relief. Move the baby's body away from yours, or into yours, or change the plane that the baby is nursing on by adding pillows or taking away pillows from underneath baby.
Breastfeeding should be comfortable for both you and your baby. If the way that is normally described works for you, then great! However, if you're experiencing discomfort, and everything else seems normal, then don't be afraid to shift baby around a bit and try to find something else that works for you. You may feel like you're starting nursing gymnastics, but the end results (no pain!) are well worth it.