painful lump in left breast

Last night I went to bed at around 10 o'clock. At about 2 in the morning my dog woke me up and I noticed pain in my left breast. I reached over and felt a small lump that had not been there when I had gone to bed. I looked in the mirror and noticed that it looked slightly swollen and it felt warm. It is right underneath of the lower part of the nipple. There is no discoloration or indentation, only slight swelling. During the course of the day the pain did not go away and the lump has gotten bigger. Is it a cyst? Or something worse? I am 17.

[Cleveland Clinic]

Dear Asalyna:  Skin on the breast is like skin anywhere on the body and is subject to a variety of abnormalities.  This could be as simple as a pimple.  If this does not go away or gets worse over the next day or two, you should call your doctor.  Breast cancer would be extremely rare in someone 17 years old.