Sounds like an autoimmune disorder which can be triggered by all sorts of things including viruses. A regular doctor won’t be much help. They just throw their hands up and throw meds at you. An osteopath can help since they look at the whole system and don’t rely on medications alone. We went through this with our son. It was triggered by a lingering sinus infection. A year seeing regular doctors and no help. Within three months being treated by an osteopath he was living a fairly normal life finally.