Hi.
I had TOS Before I had the rib resection and then developed RSD because of the surgery. So, yes, absolutely, repetitive motions are hard on RSD and can develop TOS.
I am also at a desk all day, typing, doing things at the desk that are repetitive.
Things that help? Not working unfortuntely. I haven't found anything other than possibly getting up every 1/2 hour religiously and walking around and trying to do other movements to loosen up. I do also have a heating bag that I put in the microwave and put that on my forearms. That seems to help a little bit.
I do find that I'm better in the morning. Once the afternoon comes around, I really get miserable. It seems that 1:30 or 2:00 is the magic time that I really start feeling the strains of working.
I do have to say, I try not to do very much on the weekends. That seems to help so I start as fresh as I can on Monday morning.
I know I'm not much help, but just so you know, I feel for you. I understand how hard it is.