I'm 17 and I just decided to join the school track team. This is a big deal considering I have despised running ever since I can remember because I have no endurance for it. I used to tell myself I just wasn't in shape, but lately I have been considering other factors. There is the obvious symptom of my difficulty with exercise, but I also will have trouble getting enough breath at random times that seem to have no significant connection to one another. I'll feel like I am breathing very deeply but just not getting enough oxygen. Anyway, my brother has it so I'm guessing I may have been tested at some point in my life which I do not recall. I really want to run and I don't want to let this breathing issue get in my way any longer if I can help it. Does it sound like I could have asthma?

Yes, very possibly! Mine was never VERY obvious either until I exercised or had a bad cold which would always turn into a cough. I was finally diagnosed at 41 years of age! It could have been diagnosed earlier if I had been athletic (which I wasn't). But your family MD can recommend a lung function test which can definitely tell if it's asthma.