It was similar for me a year ago. I pushed through and took hour long walks for about a year, and was totally beat after each walk, but I think it helped a lot. I made a point of walking in full sunlight and getting tanned and sweating some. My rationale was, walking trains several systems simultaneously and vitamin D would be necessary - I was already a health nut before covid, so I knew about vit D, but it helped that the whole internet was saying get D. My other symptoms were chest pains, a shooting ice feeling down my left arm, blood pressure up to 170/120 every day all day, veins bulging out and looking gross, and tinnitus so bad it sounds like a jet engine - the tinnitus is still with me, but it's reduced during and after exercise. The first time I got the breath shortness, I panicked and fell and damaged my wall. It was the short breath that got me walking initially because that was the only way to get it under control. Nattokinase helped a lot, but I never trusted it, so I only take half a pill every other day. Doctor didn't help - he told me it was anxiety and sent me home, but he did say the vitamin D was a good idea.