I have very weird dreams and frightening dreams and I sleepwalk a lot (my Dr reckons it's caused by the MS Contin I now take) and do really weird things while I sleepwalk! And I have insomnia, so my RSD (and medications for it) has really screwed up my ability to sleep normally!
But as for whether I'm in pain in my dreams, that's a no. When I'm in my dreams, I walk and run and do things like I used to- pre RSD. There's no pain, no disability... if only it could carry on like that when I open my eyes!