Concerned I might have asthma?

I know self diagnosing is stupid, but I want some input before I go to the doctor. A couple weeks ago, I got this really bad cough. Like, a whooping cough out of nowhere. It's been about 3 weeks and it's still a pretty deep cough. I'm not sick, I don't have a cold/flu, none of that... just a really deep, dry cough lol. Also, high school basketball season has started. I have been playing for about 4 weeks now, and I get out of breath very easily. I'm not sure if this is an "out of shape" kind of thing, or something more. I catch myself doing these little automatic deep breaths where I kind of strain my neck and gulp for air. It looks really weird but it happens automatically, like my lungs are trying to fill up. Hours after practice, I still feel out of breath and my chest and stomach will hurt. I am not fat and have been moderately athletic all my life, so I don't understand why it has become such an issue for me. I just don't want to be in agony during practice anymore. I also want this chronic cough to go away. Where would I go to inquire about this? Any regular doctor? Walk in clinic?