Wow I came across this post today after years of searching for answers. I started to have this same issue in about 2017. I thought maybe I had developed a food allergy so I got tested but nothing. I have seen a pulmonologist, ENT and my primary care doctor. No one seems to be able to tell me there is a noticeable physiological problem. I do think stress and anxiety somehow makes it worse.

Going to try the Buteyko method and see if that helps. Happy to answer any questions.