My biggest indicator that something was really wrong was when I would lose my gait when running. My legs would stiffen up to the point that I would lose control of them a few miles into a run. I started tripping a lot and even fell a few times. It got to the point that my legs felt like they were made of cement and even walking was a chore. Then, my arms started feeling very heavy. I didn't notice it as much. My pcp was convinced I had MS. She still tries to tell me this. But my neuro has assured me that all of my issues are SFN.