Breathing Issue with Chest pain.

My wife had Covid in 2020 before that she never had any breathing issue or anything. After Covid she was perfectly well but after few months she complained that she faces breathing issues like breathlessness, chest pain, chest heaviness as well. We have completed all the tests as well like Ashtama, chest x-rays but still everything is clear no issues were found. So it is somewhat difficult to track what is the problem. She faces breathing problem for 3 4 days or sometimes a week then she feels fine then after sometime again she starts feeling the same. We cameacross some ayurvedic doctor and he said that there is cough in her chest and due to that she is facing these issue and that is strange because all the x-rays were clear. But we tried his Medicine since nothing was working but after few days she started feeling well. This was like 6 7 months back. Till today she faces the same issue but I don't think it's cough because she doesn't have any cold or fever. So need some suggestion.