+1 for the cough-variant asthma - was recently diagnosed and an inhaler helped a lot. Overall, though, I would not be making medical decisions based on feedback from likely non-medical providers on an internet forum. Even if we were all medical doctors, it's hard to make diagnosis w/o seeing you.
IBM's Watson can do it.
Unfortunately most humans don't have access to the same databases of medical information as Watson and are not as logical (people will say it's what they're most familiar with. It sounds like it could be asthma to me, but that's probably because I have asthma - Watson wouldn't make those kind of mistakes). So maybe I can amend my recommendation - go to a doctor or Watson ;-P