When I was in my 20’s (college years) I had severe air hunger. Never smoked. I spent all day, every day, trying to breathe deep enough to get sufficient air into my lungs, but only on a rare breath could I do so. It became exhausting and worrisome. This lasted for well over a year.

This may not be related to you, but thought I would post it in the hope that it is helpful.

Bronchiolitis obliterans, also known as "popcorn lung", is a rare chronic lung disease that can be caused by inhaling diacetyl, a chemical used to flavor microwave popcorn.
Diacetyl causes the lungs' tiny air sacs to scar, which thickens and narrows the airways. I’ve never had the breathing issue again after I stopped eating microwave popcorn.