Do I have breast cancer?!

At 17 a primary breast adenocarcinoma is so rare that it should make the cable news channels if it were ever proven. As others have said, best to check with your doctor and monitor this yourself for progressive growth. Most primary breast cancers are not at all tender. This is probably due to benign hormonal changes in that breast. One grandmother with a history of breast cancer over age 40 does not increase your risk. Think of this as about the same risk of being hit by lightning. The odds of breast cancer at age 17 and lightning hitting you this year are weighted in favor of the lightning. You probably don't lose sleep worrying about lightning, but you would probably take precautions in a thunderstorm.

MD hematologist and medical oncologist - cancer and leukemia specialist physician for 20 years

No, I highly doubt you have breast cancer. Breast cancer is only genetic if you have the BRCA gene and skipping a generation is not true. If your grandmother got breast cancer in her later years and she is the only person in your family to have had it then it doesn't put you in a high risk. 17 is far too young to get it. Go and see a doctor as they will make you feel a lot better, but don't go worrying unnecessarily as lumps in a 17yo breast are normal.

No. This is related to your growing breasts. The fact that it hurts is in your favor. Just a simple cyst. See your doctor, he can put your mind at ease in 3 minutes.

Breast Cancer Survivor

no one knows your body better than you so you should see a doc. It may be nothing but don't chance it. Good Luck.