Well my doctor had me to chin to chest but I didn't feel anything. I do it on my own all the time too and don't feel anything so I don't think it's lhermittes sign. It is literally just a random zap of pain that is local, and sometimes it pulses.

I do get muscle twitches from time to time that are painless, but for my sanity's sake I associate it with high anxiety. Otherwise, I don't think I've felt a spasm if it's more like a muscle tightening feeling.