I get that problem... it makes me worry because my cousin had this disease where it gets hard to digest anything without pain so she ate anorexic amounts just because it hurt so much. Sometimes I start to worry if I'm gonna get that...
Not to worry you though, I'm just worried cause it's in my family
but sometimes I get the same thing, where I just can't eat anything. Sometimes whatever I eat comes straight back up, at its worst... maybe you have an allergy? Try cutting out dairy products, or wheat maybe, also I had asthma and eczema in the past and my doctor told me to try cutting out dairy for one of those but I can't remember which... might help your asthma, possibly.
If it's only a recent thing you might have a stomach ulcer or something? I don't know... but if you see a doctor they'll give you proper advice
Good luck!
Oh, and the thing about working out, that's normal - I get it too. I can't remember what the logic was but that's nothing to worry about