Definitely get screened if possible. I've had asthma all my life- grew up in a plastic tent. And I can tell you its not pleasant. Note you'll often hear people say they grow out of asthma. Well it the inverse can often be true as well. Due to environmental conditions/age etc. you're body may take a hoit that makes you "realise" it has had asthma all along. Its like allergies that are lung specific. You've basically got an hyperactive immune response that inflames you lungs when exposed to some allergen when you have asthma. For some people it might be just waiting for the right allergen and allergy treatments may be sufficient (or a change of venue). there ARE other reasons for shortness of breath due after exercise though- including heart problems etc. so screening is always good. If you want one of my platitudes-Doctor IMO are best for diagnosis, though treatment is up to the patient.