One nipple is bigger than the other, is that normal?

Thanks for this question on nipple size. It is normal for there to be nipple asymmetry with regards to size and projection. I perform nipple reductions routinely and the results are very nice. Best, Dr. ALDO

this is very common but it can be addressed to surgically if it is a problem for you. The operation is quite simple and has no concern for pain.

You don't give your age or whether this is a new problem. Given that and the fact that your nipple is sore, I would see a breast surgeon (someone who specializes in problems of the breasts) this is not necessarily a plastic surgeon. It is possible that you could have some blockage in the ducts. If this exam reveals no abnormalities then yes, one nipple can be larger than the other for a multitude of reasons including breast feeding.