Sounds like spasticity. I remember once when I was very tired, at the end of a day teaching school, my arms were on the desk and I could not move them. Eventually, a few minutes later, I was able to move them. But I recognized that I was too tired from overdoing at work. At that time I had no dx.
I have had several episodes like this, but my spasticity is usually less paralyzing. Muscles can get rigid anywhere in my body. And the nerves are eventually damaged in those areas, so that there are twitches or jerking, which happen mostly in my legs or lower back, rarely in my arms, but sometimes affecting the whole spine with a jerk.