[I got that feeling a few times I couldnt get it to move ---once trying to get up in the middle of the night to go to bathroom ---then follow up with what I call painful zingers-- which last alot longer. I chalked it up to nevre being pressed somehow by the way I was laying. Not 100% sure when it happens its very freaky. I have sfn too my cause it from thyroid which was found later, I also have cancer and neck fusion. My leg symtoms are always from sfn.