I'm 17 And Have A Small Lump In My Right

I'm 17 and have a small lump in my right breast, it's been there for over 2 year and have gotten it checked twice in the 2 years. they say it's something like a growth? not sure. but it doesn't hurt nor has it ever. it seems to have gotten bigger recently and now I have a yellow bruise pretty close to it. what do you think is the problem or what I should do?