I would suggest talking to your ob about it. Could be a few student things. I have a long fatty tumor along the side of my left breast that sometimes gets tender and the wrong bra makes it excruciatingly painful. I also recently had pain in my right breast that was caused by a blocked milk duct, warm compresses and a warm shower helped clear that up. It could also be something not so innocently fixed, so talking to your Dr about it as soon as possible would be my suggestion to help fix your problem.