Ive also never smoked but over the years have had bouts of bronchitis in the winter. Since Covid my SOB was one of the worst and most scary symptoms, sometimes id be so out of breath just sitting on the couch. My pulmonologist sent me for a pulmonary function test after my first covid infection (4/2020) and even though I was extremely out of breath with mu HR reaching over 140's during the seated testing the test didn't show any issues with my lungs. Then after covid 3/2023, even though my SOB didn't seem as bad as before my PFT showed Asthma. I tried so many different combination inhalers, nothing helped. Then when I went to The Mayo Clinic last year they recommended a steroid only inhaler, it has helped me so much. I still get out of breath climbing stairs or when I overexert myself but it doesn't seem as bad.
To answer your question, yes go get a second opinion, a fresh set of eyes are always better than nothing.
Good luck xx