I am a 15 year old male and i have a disk-like lump under my nipple. It moves and hurts when i press it. what is this? Help?

It could just be a harmless cyst. Breast cancer usually isn't painful - and I think gynecomastia would be more than just a single lump. Tell your parents and see a doctor. I'm sure it's nothing to worry about.

Stop pressing it and tell your parents. 15 year old boys can get breast cancer. You're probably OK, but go rest your nerves with a visit to the dr. Peace

Get examine by your doctor right away.