What Causes Chest Pain And Numbness In Left Side Of Body With Normal EKG?

I have a son who just turned 20 years old. He has been an athlete his entire life. He even got a scholarhsip to play basketball in college. The summer before he was to leave for college, he started getting severe chest pains. in the center of his chest. He was unable to take a deep breath and he ended up passing out due to hyperventalating. He has had EKG s, sonograms, and such and cant find anything wrong with his heart. the doctors are pretty stumped. they have ruled out anxiety. These attacks come on and last up to 20 minutes. He tried going to college to play, but would collapse on the court. his last attack was the worst ever. He was in the shower when the pain started. He called for help and we had to drag him out of the tub. he stopped breathing and my husband did CPR. He lost all feeling on his left side, even his toungue. I pinched him really hard and he didn t feel a thing. He has no recollection of what happen. The attacks, we will call them comes on now even when he is not doing anything to get his heart pumping. My oldest son who is now 27 had the same thing after he graduated from high school and the doctors didn t know what to call it. He didn t play ball for a year and the problem seemed to go away. He just finished another season of ball and just told me he has had 2 attacks again. As bad as they were for him a few years ago. What could this possibly be that both boys have the same thing? My youngest is 6 4 and 150 lbs. My oldest is 6 3 and about 210. My youngest is going for a stress test this week, but I am guessing they wont find anything wrong. I don t think its a heart issue, but I don t know what could be causing these attacks that his doctor says the pain is like having a heart attack but it isn t a heart attack. thank you for any help you can give me.