I get muscle spasms too. Mostly in the effected arm but also it travels to my neck and back. I also without warning start shaking like convulsions. My head shakes up and down and it's happening more frequently than before.
The last time I was at PT the therapist saw it happen and documented it which was good. Well, not really, but it was good for someone medically to see it happening.
I'm seeing the neurologist next week and I will bring it up. She's very good at treating RSD so I'm sure something will come of it.
I guess these tremors are one more thing that is common for us...