16 Year Old Having Pain In The Chest And Ribs. Growing Pains?

I am 16, male, 130lbs. and about 5 10 . For some reason I am experiencing chest pains. Last year I had these pains right where my heart was and thought it was and emergency. my doctor diagnosed it as growing pains. Now I am experiencing pains just below my sternum to my left side by my ribs. These pains are more painful, and unlike my growth pains, holding my breath and pushing out on my ribs doesnt work. The pain is sharp and stabing feeling and it only occurs a few times a week, but they only go away when I breath through them.