Lump in the breast?

Kristie, 

What you have sounds like the normal tenderness of developing breasts during puberty.  As you develop, sometimes one breast may be a little more lumpy or bigger than the other.  Twelve year olds almost never have breast cancer.  Most breast cancers are not genetic, so your grandmother's breast cancer may not affect your risk for getting breast cancer when you are much older.  Since this hurts and is worrying you, I would suggest that you talk to your mother, school nurse, or doctor about this.  Sometimes girls your age do have breast problems that need a doctor's attention.  It's good that you are paying attention to your body.  

Kristie, I commend you for being so aware and proactive when it comes to your breast health.  I wish others were so aware!

In my opinion, I think that at your age it's likely typical hormonal changes - as they do tend to cause tenderness of the breasts, and it's certainly a possibility that the hormones can be causing cysts that will come and go with your cycle and hormones - if you have dense breast tissue it could be fibrocystic tissue....there are so many types of benign lumps that it could be.  Cancer would be extremely rare for your age, even with your family history.  Sometimes genetics has nothing to do with it - I've had breast cancer twice now by age 34,  I was the first in my family to have cancer and I'm not a gene carrier either.  I swear sometimes it's like there's no rhyme or reason to it.

Like Phyllis suggested, talk with someone that you feel comfortable with.  Monitor the lump over the next few weeks and if it doesn't go away, or if it gets larger or changes shape then definitley see a doctor.  There is no reason at all for you to worry or stress over it, especially when you can get an ultrasound done and know if it's abnormal and should proceed with some type of biopsy - but you really shouldn't be worrying yourself sick over it.  I'm sure it will all turn out to be ok!

Good luck to you!

Angi