so i'm starting a new thread for you. We can't tell you that your lump is absolutely nothing to be worried about, because only a doctor can do that. However, at 15, I'm sure your body is going through lots of changes, and lumpy, bumpy breasts are often a part of that. With fibrocystic changes, lumps and bumps can be very sore and tender, and lumps can be quite large. These should change throughout your monthly cycle...some days they may feel enlarged and quite tender, and other days, you may not notice them at all. Typically, these lumps are not related to breast cancer at all, but are related to your periods and fluctuations in hormone levels throughout your monthly cycle.
Have you talked to your mom about this? If you haven't talked to a doctor about what to expect from changes in your body, this would be a perfect time to do that.
Usually, but not always, breast cancer is not painful. The cancerous lumps usually grow very slowly, so they gradually get larger, but they do not change throughout a monthly cycle.
Fibrocystic breast disease can be very painful. If that is all it is, it still warrants a trip to the doctor to talk about how to deal with the pain.
And good for you, for checking your breasts yourself! If you learn what the normal lumps and bumps in your breasts feel like, then you will easily detect any lumps and bumps that are "different" in the future.
Let us know how things go for you, kiddo!
"There's a difference between a philosophy and a bumper sticker." --Charles Schulz