I'm not sure what topic to put this under. I am female, 42, non-smoker, I do moderate excersise. I have had this before (and never did anything about it), but not for a few years. I have had it again for the past few days. I get a charp stabbing pain just under and behind my left breast, toward the middle of my chest (in the past I have also felt this on the right). It happens when I breathe in, and it is very painful. To alleviate it, I stop my inhale, and control my breaths, keeping them small, and gradually breathing in a little deeper, stopping when it hurts, and continuing until the pain subsides....it takes a minute or so for it to go away. There are no other symptoms, no lightheadedness, no feelings in any other parts of my body. It happens any time of day, about 5-6 times a day. I don't notice it at night, and I am sleeping fine. Any ideas? Thanks