S.R.
It sounds like some type of allergic reaction to me. Usually if it's related to the actual breast, it will discharge from the nipple. Have you been outside in a swimsuit where you could have gotten a bug bite? Are there any other places you are itchy? Do you have allergies or skin sensitivites? Eczema? It is good to have it looked at, but the fact that it's itchy probably narrows it down to infection or reaction. Doubt it would be a growth or anything like that.