Body Question?? PLS HELP

So within the past few months my boobs have been super sore. like to the touch. they also seem to have grown a lot. I basically use to have none whatsoever a few months ago. wasn't even on the charts but now even a 32B seems tight. i looked up on the internet what it could be but it usually says i'm pregnant which is obviously not the issue because i'm on my period now. does anyone have any suggestions as to what it could be?? I'm 20 so i doubt it's puberty but i'm kind of worried because they hurt really bad.