Here is the back ground on this. When I was a little girl, around 6 yrs old, I had a pain in my chest. My mother did not and would not take me to have this checked out. The pain started suddenly, and only hurt when I would inhale or exhale normally. I sat for a long time doing rapid shallow breathing. Each time I would try to take a normal breath I would feel the pain. I don't know what made me do it, but I finally took a very deep breath and exhaled until I could not force any more air from my lungs, I felt a "pop" in my chest, heart, or muscles around the heart, then the pain went away. I have had these attacks pretty much my whole life. I have gone to the hospital a few times for it, but I still have no answer for this. I am almost 38 yrs old now and these attacks are happening more frequently. And my 17 yr old son just called me (lives with his father in another town) and told me he is having the same thing happening to him. I would love to find out this is so that he and I can find help in stopping this. Does ANYONE know what this is??