Q:

I have a grape sized smooth lump under my left nipple. I am an 18 year old male. I have had one before and went to the doctor and was told it was nothing. This one is slightly larger and makes my nipple slightly tender, not very bad though. It's kind of annoying. What could this be?

 

A:

This is most likely gynecomastia which is the development of (often tender) breast tissue in male adolescents, which is a normal developmental finding and usually resolves on its own.   It is also more common in those who are using alcohol and marijuana regularly so if you are drinking or using cannabis, it is best to stop.

You'll find more information at http://www.mayoclinic.com/health/gynecomastia/DS00850

~The Doc