get a
breast exam ASAP. It could just be some kind of inflamation or sore muscele, but never take the chance. If you just started having sex a year ago, I can only guess your still a minor. If thats so, have your mom take you in for a
breast exam as its likely you are under her insurance. Btw, I dont think sex has anything to do with pain in your
breast. Unless your patner is being too rough in that area by grabbing or pinching too hard.