I’ve been following this thread and feel that you could signficiantly benefit from trying out acupuncture. First it could reduce the pain and address the breathing problems you mentioned. Second, it sounds like you are rather stressed in general…and it can completely reduce stress as well.
Also going to a chiropractor might completely “open” up this area of your chest and make it feel good again. For instance the lung bones are connected to your spine, so if you get your back cracked, your lung bones will go into a proper alignment. There’s a thing they can do called the “unzipper” where they crack the point in the middle of your back…this can completely “open up” the chest and allow you to breathe more easy. I sometimes get chest pain but it goes away after visiting the chiropractor.
I think the cause lies in inflammation and the candida diet can help reduce your inflammation in the long term.