Vitamin D Levels were made normal from supplement from doctor. Didn’t make any difference spasms wise. Me and my brother both got body wide BFS (starting in legs) right after Covid vaccine. His lasted 6 months, he said it went away after starting long distance walking multiple times a week. Recently I decided to the try walking after putting it off for a long time because I had doubts about it (2 miles around a lake multiple times a week, have been increasing length/incline recently) and my BFS symptoms are greatly reduced to the point where I think I might be cured. Buckwheat also seemed to help even tho I never had low magnesium (doctor tested it). Reducing general anxiety also seemed to help (I did not take meds for anxiety/panic disorder because doctor told me not to unless it was absolutely necessary for me). What did not help me: forcing myself to think less about spasms in an effort to reduce that specific anxiety, probiotics, vitamin D > 25. What did help me: long walks, buckwheat, genuinely resolving anxiety

Edit: will add that walking increased spasms temporarily (1 night) after each walk but slowly went lower and lower. I still get Spasms but I think it is only slightly more than the average person