Hi, breast pain can occur pre menstrually. Tender sore breasts at your age could be due to pregnancy, fibrocystic breast disease due to hormonal imbalance, infections or inflammations of the breast to name a few. If the pain is aggravated with work or exercise then it could be due to cardiac pain. But when in doubt always best to have it checked. So please consult your primary care physician who may ask for an EKG or a treadmill test to rule out a cardiac cause for the pain. Regards.