Brittany I commend you for being so aware of your body at your age, and taking it seriously!  Most people refer to breast cancer as something only older women get, which is NOT true.  It also does not have to run in your family. But at your age your body is still going through tremendous changes.  The lump can be nothing, some women just have lumpy breast tissue - or it could be a cyst that changes with your period, that comes and goes.  and another very rare possiblity is that it could be cancer - the only real way to know for sure is to see you doctor.  Do you have someone you can share this with that can take you to be checked out.  I'm sure it's just hormonal changed, but it's always better to be safe than sorry.   Good luck! Angi