Two things
Recently Ihave had some issues but not as serious as you are describing. It seems because I am bent the way I am and my spine has the problems it has that my shortness of breath may be neurological in origin since echo- stress test and other things indicate it is not cardiac although I do have greatly limited chest expansion. Oddly in my case walking after eating also seems to be a large strain.
Second, maybe its not necessarily AS related. Diane has liver issues which exacerbate her asthma. However, she seems to be very allergic to certain things that can make breathing very difficult
