We're all different, but for me it was hormonal. To get to this diagnosis, I had two years of tests, MRIs, brain scans and horrible drugs which made me feel worse. I had so many MS symptoms, I ended up seeing two different neurologists. Most of the time I had numbness and tingling, but this sometimes switched to aches and cramps. Had to give up running which really upset me, being a keen runner. Eventually one of the neurologists sent me to an endocrinologist - and that's where I found out I was so estrogen deficient.
I have since spoken to a colleague in her 20s who had exactly the same thing, but so badly she was hospitalised. Again, hormonal fluctuations were found to be the cause and she has been on the pill since (POP for some reason so no estrogen).
Apparently, there's a train of thought that it is due to water retention nudging nerves - similar to the carpel tunnel symptoms pregnant women get.
I really feel for you. It's horrid. What upset me most - and still does - is well meaning people saying the best way to cope with meno symptoms is exercise. There were days when I could not cope with putting shoes on, let alone exercise (and that's coming from a life long fitness fan!).
Big hugs x
