16 year old boys "heart Hurts" complaints

My 16 year old son has been complaining of his heart hurting ever since he was approx. 5 years old, but I wrote them off as growing pains. This past year his complaints have become more frequent (monthly, if not more) and I took him to see a cardiac specialist yesterday. The specialist ordered an echocardiogram which showed normal heart wall, good and open heart vessels, arteries, etc. and a healthy heart rate and blood flow. He did see some backflow in one of his valves, but said it was nothing serious to worry about. He said he is suffering from a form of Plureacy and that it was nothing to worry about. My son suffers with sever chest pain and a shortness of breath, which lasts anywhere from 5 min. to 2 hours. These attacks occur when he is just sitting around and not excerting himself. The doctor said we should only worry if these attacks begin occuring during excertion and / or are accompanied with feeling faint, light headed or actually passing out.
Is this a true diagnosis or should I pursue another opinion?
Is this normal for teenage boys to experience, and do they grow out of it?
What "exactly" is he suffering from?

Hi - is your son suffering from any form of stress or anxiety because these are both signs of that also. I would go and get another opinion i think just to be sure. I started with chest pain last year when i was resting and saw my doctor and they did ecgs chest xrays and blood tests and then an echo when i saw the cardiologist. Why not ask if your son can have these other tests too?
At the age of 16 heart problems are unlikely and if the cardiac specialist doesnt see anything to worry about im sure all is fine but if you are not convinced please go and see another doctor to put your mind at rest