Someone else's mysterious breathing problem

[nancylebov]

Alicorn says:

Well, in the department of actual running, I have some kind of mysterious lung issue that means I need to gasp for air a lot even when I'm sitting still and have been for hours and it only gets worse if I try to do exercise more strenuous than a leisurely walk. (Armchair diagnoses appreciated, incidentally - so far I've stumped multiple doctors and new Google keywords are good.)

and it occurred to me that there's enough medical knowledge on my flist that it might be possible to get some reasonable hypotheses about what's going on with her.