Mine was definitely due to anxiety about a difficult life situation, although it felt like a physical problem, as you describe. It was a buzzing feeling in my body. It was several years ago but as I recall, it was not constant. I think it fluctuated with my anxiety level. I also had some chest pain which was also attributed to anxiety. I was prescribed an anti-depressant/anti-anxiety med and Ambien for sleep, and worked with a therapist on my coping with the life situation. I hope the psychiatrist is helpful but if not, keep looking for the right practitioner for you. With rarer or unusual conditions, it can often take many tries to find the right one who will investigate it properly and find effective treatments. If you have friends or other docs you trust, check with them for referrals.
In the meantime, look for activities that bring you even temporary relief/relaxation and build them into your days/nights -- warm bath, reading favorite books, favorite movies/TV, listening to and/or playing music, exercise (walking swimming...), writing/journalling, yoga/meditation, being outdoors, being around other people, listening to uplifint podcasts... Courage! And keep us posted.