I am a 19 Year Old Male, who is 6'6" and weigh 140LBS. Ever since I was about 9 years old or so, i have had to give up all strenuous activity. When i run, or play any kind of Sports i get an extremely painful crushing pain in my chest, i get a very metallic taste in my mouth (no blood) but an increase in saliva. My head starts hurting really bad, my vision goes black, i get very dizzy, and cannot stand on my own. Its extremely debilitating and lasts for a good half hour or so, and i feel off for the rest of the day. They have done countless ECG tests, an ultrasound, wore a holter monitor, and a test where they hook up an ECG machine, and get me to run on a treadmill to get those symptoms. The symptoms came, but the test was clear. All my blood work was normal, Every test has been clear, but to this day, i still cannot do anything physical, because the symptoms always return. I know my heart doesn't do this for fun. There has to be something.