@captainanxiety8 You are describing my symptoms to a T. Mine started about a year and a half or two years ago. I kept having strange sensations all over my body and twitching from the top of my head on the scalp all the way down to my feet including pecs, abs, shoulders, all over back including lats, eyelids, facial muscles, neck, glutes, thighs, calves and the inside of my thighs just below my privates. I also get aches and slight burning sensations all over my body. The pain and sensation is never severe but it's there. I describe the pain as being similar to an old injury so it's dull. I often get pains in my knuckles and the various joints of my hands and feet. All of the symptoms come and go. I can have weeks of hardly any symptoms then I get a flare up which is usually accompanied by insomnia or sleep disruption. I sometimes get itchy skin too which is a nuisance when I am trying to sleep. I noticed that when my skin itches I tend to sweat a lot overnight in bed but this doesn't happen all the time.
I had an MRI scan on my brain and spine and both were normal. I had countless blood tests which all came back normal. There were no antibodies for Lupus or Isaacs Syndrome. No deficiencies or anything abnormal. I am waiting to get an EMG (Electromyography) test.
The Neurologist conducted the same tests you described your doctor did on you and all of that was normal too.
She said I might have Isaacs Syndrome (but this was before the blood tests which showed no antibodies which are found in around 50% of people who have Isaacs Syndrome) or I might have BFS.
I think it's probably BFS because it is very common and I have been under a lot of stress related to full time work and full time university commitments. Isaacs syndrome is also less likely because it is extremely rare. So far only around 200 people are known to have it worldwide.
Despite the annoying symptoms (the insomnia and anxiety being the worst) I feel totally fine. I haven't lost muscle mass or strength and my coordination is normal. I go to the gym regularly where I lift heavy weights and do intense cardio.
I really think it's BFS which is not fatal, progressive or serious in any way. It sounds like you have the same so I wouldn't worry too much about it because stress and anxiety make it worse. I hope I have helped putting your mind at easy. Stay healthy. All the best. Harry (From Glasgow, UK)