What Causes Pain Over The Left Breast?

Hi, Im 14 years old, imma female and i am very active. I play hocley and softball, also basketball/ . i think im a little over wieght for my age but other say not. lately, i have been experiencing some chest pains over my left breast, and its somewhat not constant, but it comes every so often, i suffer from anxiety disorder and well i guess its the same but panic disorder, i got told that all of these things like dizzyness , chest pains, etc, are normal. but as i say. get paranoid really easy and i would like an answer. so please. and thank you. HELP ME ! and it feels like a little dull pain. nothing too sharp. but uncomfy, .