I battled this for way over 20 years. I will give some thoughts about what helped me.
First, in my case I thought it was RSI, I was diagnosed with RSI multiple times, but when I joined a research study into RSI I found it was not RSI. They did find elevated muscle enzymes indicating damage, but the cause was not identified.
In my case I think its a complication of ME. Muscles need rest. Continuous use for me resulted in pain that kept getting worse the more I did. STATIC muscle stress was even worse. Continuous low level stress. If I was holding a position by muscle tension it made things much worse over time. This included postural muscles.
Almost nothing helped early on. I tried ergonomic furniture, muscle rubs, anti-inflammatories, painkillers, and so on. I had acupuncture and Chinese herbal liniment. Actually the liniment helped a little, just not enough. Back then I was not even diagnosed with CFS, and the only time I had heard of ME the media got it so wrong I was sure I didn't have that. The only drug that helped was Vioxx, but I knew enough biochemistry to not take that very often, just to take the edge off when it was bad, and warned my doctor the drug was likely to be banned. Six months later it was. It kills synthesis of critical hormones, and that is very dangerous.
I did physiotherapy for a year, exercising and icing my muscles almost every day. Things got worse, and stayed worse.
I am right handed but was forced to use a mouse in my left hand. To this day I still do that.
Then I was diagnosed with CFS. A little later I discovered a menthol muscle rub, that gave me immediate relief but was no cure. Along the way I fell into pacing without having a name for it. It helped.
Fifteen years later, when I was much better at pacing and had made many accommodations the pain started dying down. Five years after that it was gone on a daily basis, but if I aggravated my muscles then it got worse again.
My hypothesis is this might be due to low mitochondrial reserve. When we have a sustained effort beyond the muscle capacity it gets damaged at the subcellular level. Its only an hypothesis though.
If I was doing this all again I would find alternative ways to use my muscles, get more rest, find supports that stop me having to hold my arms or anything else in a specific position. Light stretching as the only exercise. I switch up my activities, putting different strains on me, so I am alternating or rotating between different muscle and brain stressors, and I should have started that earlier. Even now I have a menthol muscle rub on hand just in case, but the tube is starting to look old now.
In my opinion its better to try to deal with this now before it gets worse. Twenty years is a long time to wait for recovery.
Another possibility is I started taking inositol hexanicotinate. Its a niacin equivalent. I am doing this to raise my HDL. The therapeutic dose of niacin is between 2 to 3 grams a day in clinical trials. At a bit under 2g per day I noticed two things, both in the last few days. The first is my residual muscle pain issues have greatly lessened. The second is I went from under 5 hours sleep a day to over 8. The usual caveat applies though, this is the last thing I tried and so is associated with at least temporary improvement, but that does not mean its the cause.
