I like the armrest idea, that makes sense. I certainly think ergonomics (and rest) are key. But there are other things that help, too. I have had years of relief from doing a few rounds with a comfrey root poultice. There's some controversy over comfrey root because if you feed a bale of it to rats they have liver problems. I feel bound to say that, but I also feel bound to say that a little through the skin is very different than a lot through the digestive tract. If anyone's interested in the method for doing this poultice, please ask. It got me from being in pain from picking up a paperback book to getting my hand and arm back again for many years. I'm thinking of doing it again. It was a sloppy mess but it worked.
Many years later the pain came back from a lot of repetitive use; this time I tried a series of liver cleanses, but I don't know if this is a great idea if you have CFS (I did one liver cleanse when I first got symptomy, thinking maybe that was the problem. It just made me feel worse). However it was effective for two or three years, so worth mentioning. The theory is from Chinese medicine: the liver/gallbladder meridian runs up the right neck and shoulder. Unclog the meridian, unclog the shoulder. (I'm sure there's more to it than that, but that's the simple version.) Liver cleanses are also beautifully calming, at least afterward.
I go to an acupressurist who really knows her stuff and can get me from screaming nauseating pain to functional in an hour and a half. I try not to get to the screaming pain part, but it's great to have a resource when I do.
More homely remedies: I use arnica, but someone introduced me to Myoflex (comes in a tube, available at drugstores) which works differently. Sometimes one does it for me, sometimes the other.
Here's another homely remedy I got introduced to: infrared light shone on the sore area from a distance of about 18" away for 15 to 20 minutes. I'd learned that muscle pain responds best to cold, but apparently nerve pain is different; a session under a heat lamp can really really help. And it's a pretty cheap fix, too. (You can use a clip-on lamp to direct the light where you want it. My hardware store guy warned me that you want to get one with a porcelain, not bakelite, holder for the bulb; the bakelite ones disintegrate in a few months. I got a chicken brooder lamp.)
Meier Schneider has some movement therapies for this - he's very good - and I've also recently had some work with a Somatics practitioner that is very encouraging. It's about retraining your brain and body to get out of the habit of pain using very gentle movements. It's not about getting range of movement or so many reps, it's about really feeling what's happening in your body, and learning to move in new ways.
This one may be controversial for some, but marijuana oil really helps my nerve pain. I understand that the tincture is better if you want fewer of the mind-changing effects but you do want relief of pain. I might try that since I certainly can't go out or operate heavy machinery when I take marijuana oil. But since it is my stalwart sleep remedy, the pain relief is very welcome (and probably part of the sleep remedy effectiveness).
Can you tell I've had a few rounds with RSI shoulder pain?