What do you do about the restlessness?

It's insane. It's bad enough that my body is unable to do normal people things and needs to rest all the time. But while I'm resting it also needs to freaking revolt against me, spasming and jolting and making it impossible to sleep or stay still. It feels like restless legs syndrome, except it covers my back as well as my legs.

Cannabis helps, but it would be nice to get relief without getting high. Any advice?