I’d be curious to learn how many who are suffering from shortness of breath post-Covid may be experiencing costochondritis (among other conditions). This condition was found to be responsible for 30% of chest-pain emergency room visits [MedScape] and is known to be caused by viral infection [WebMD]. While it is often seen in primary care, it is apparently rarely referred to physical therapy though stretching has been shown to help provide relief [1]. One physical therapist developed a simple device to facilitate stretches called the BackPod (I have no affiliation with this/him) which won a Red Dot Award in 2013 [2] and I know some have turned to for relief.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5455195/ [2] https://www.red-dot.org/project/backpod-6994