Mine was hard and didn't move and it was nothing to worry about. Just wanted to state that. Also, I forgot to suggest a warm compress that is what they told me for the discomfort. Good suggestion silverfox67.
Because she has discomfort, it could be a clogged milk duct or fibrocystic disease. Try some warm compresses to see if that helps. If the lump is hard and doesn't move, it could be serious. If it is soft and moveable, it could be a benign lipoma or just a clogged milk duct.
I know when I was 15 and had the same issue cone up my mom was able to find a medical program for kids. I believe here in Texas it is called chip. There are also clinics like planned parenthood that could point you in the right direction. You should try not to stress so much though. Don't put it off but don't stress as well.
My lump ended up just being a cyst. I have has a few over the years. But every doctor says they are nothing to worry about. So a lump could be nothing. Still as I said don't put it off just in case. It is always better to be safe then sorry.
Good luck, and I will be praying for you and your daughter. May God be with you,
Kimberly
i think you should see an obgynecologist for that matter.