After exercise i have difficulty breathing in with stridor. i often faint after exercise. i've had this for 10 years, asthma ruled out. any ideas?

Stress test: Talk to your doctor about a cardiopulmonary stress test. It will help narrow down the problem. You should not be exercising to the point of fainting.

Exercise anaphylaxis: I agree that you should have a stress test to be certain there is no problem with your heart. The most likely diagnosis, however, is exercise-induced anaphylaxis. Stridor is due to laryngospasm - swelling around the vocal cords. Loss of consciousness could be due to that or low blood pressure. These are symptoms of life-threatening anaphylaxis. Don't exercise until you see a qualified allergist!