My story's similar to Sparkle's. Had excruciating back/shoulder pain, then tingling, for months. MRIs revealed nothing so was sent to a neurologist to assess for MS. GP had already found my Vit D was deficient, but neurologist said this was a red herring. (By coincidence, he'd done lots of research into Vit D within his MS work). Certainly, the supplement I was prescribed made no difference to my symptoms though I was still glad I tried.
Won't bore you with the rest, but two years later was eventually found to be estrogen deficient. Now on Qlaira and symptoms much, much better (though not totally gone). Migraines have eased too. Consultant thinks it's water retention that was niggling nerves which caused my pain, if that makes sense? It's amazing how so much of our body's functioning is affected by hormones. X