Lump in breast - Teen?

Okay, So im 12 years old and i have a long hard lump in the top of my breast. Yes ive told my mom and ive cut off caffeine for 2 weeks to see if it went away...it hasnt. And im really scared. It only hurts whenvyou push down on it. And again its on the top. Ive worried myself so much. And im still really scared. What could this be?