Hi there, have you ever looked into a connective tissue disorder such as Hypermobility syndrome/Ehlers Danlos?

You mentioned Syrinx, fibro, fatigue, neck pain, limb weakness and muscle pain, which are things that can be associated with connective tissue disorders. Also bloodwork and tests often come back fine with such things.

I have hEDS myself and have recently been looking into whether i have some neck instability where part of my spine could be pressing on my brain stem and causing some odd neurological symptoms.

When i saw your list it piqued my interest because i have seen other people with EDS mention similar things and i wanted to post just in case it was something that might be worth looking in to if your symptoms are unexplained.

I hope you find some answers!