Of all the weird places to get pain, your breasts might be the most disconcerting. To get the real deal, we asked NYU Langone Medical Center's Raquel B. Dardik, MD , about the most common causes of breast pain — and it turns out most of them are totally harmless."The most common cause is just cycling in your period," says Dr. Dardik. Yep, that second phase of your cycle when hormone levels are in flux can cause your breasts to be a little extra tender. But those changes can also happen when you're on birth control pills or in the early stages of pregnancy — basically anything that messes with your hormones. Although doctors aren't totally sure why this seems to be the case, Dr. Dardik says increased fluid retention (and the resulting swelling) may be partly to blame.Sometimes, you might have pain that feels like it's coming from your breast, but "it's not the breast itself," says Dr. Dardik. Instead, it could be some sore pectoral muscles (did you do a few extra push-ups? ) or inflammation of the muscles near your ribs. So grab a couple of ibuprofen and take it easy.It's good to remember, though, that breast pain isn't generally a sign of cancer. It's also not usually caused by medications (other than birth control). But if you're worried, the best advice — as usual — is to get it checked out by your doctor . Because your breasts deserve all the support they can get.