Why do I get sharp pains in my chest?
I am 15 years old and I'm a guy. I am fairly fit, eat pretty healthy, and am outside most of the time. Recently I've been getting these sharp pains on the left side of my chest (by my heart), that feel like there is a sharp needle going through me when I breathe in. It isn't asthma and I don't think it has anything to do with my lungs (never smoked, and don't drink). I was also talking to one of my friends on my hockey team and both he and I have started working out a little bit and coincidentally, the same thing has been happening to him.
What should or can I do and why does this happen?