17 year old active male run 4/5 mi daily,ekg, echo, chest x-ray,blood work normal peak flow meter normal feel lack of air and chest pain for 3 months?

During exercise?: If symptoms only occur during exercise could be exercise induced asthma, narrowing of airways in lungs triggered by strenuous exercise. It causes shortness of breath, wheezing, coughing and discomfort during or after exercise. Treatment can be gotten with medications and certain ways of controlling temperature prior to workouts.