My dad, 64 y.o.mostly healthy, x-smoker(3mon)had stress test 3day ago&exerted himself in very dry room.since then, feels he can't get enough air/s.o.b, tight chest, dry cough.pneumonia, panic, something else?

See a doctor: Those symptoms may be signs of something significantly wrong. One cannot tell without a complete history, physical and possible lab/imaging tests. Follow with a doctor promptly. Things that can cause pains in chest and abdomen include heartburn, pneumonia, gallbladder problems, liver disease, kidney problems, heart attacks, or blood clots.