Just to be definitive, I suggested the kinesis Advantage2. It should help with your non-mouse hand. There are plenty of reviews of people who claim it saved their careers from RSI.
Good luck! I’ve not had any rsi pain since switching to the advantage plus a trackball. I hope it works similarly for you!
* A sit stand desk. I do stand at it, but it helped the most because I could lower my desk. Most off the shelf desks were too high for me and it hurt my arms
* Raised the monitor to proper height with books. It's also asjustable, as proper monitor height differs when sitting and when standing
* Investigated which keyboard shortcuts strained my left hand and remapped them. This may be very relevant for you....
* Trigger point massage therapy. This was essential, and the most helpful. Also tried regular massage. It's helpful, but forceful trigger point massage is one of the most effective things I've found. Can be hard to find a good practitioner. The trigger point therapy workbook can also be good for some self therapy. Deep tissue massage is a good place to start looking if you can't find a trigger point person.
* popsocket on my phone. Helps reduce pinky strain. Good phone positioning too, and trying to raise it up for neck positioning.
* physio. I used a physio who's worked with sports teams and does MAT among other things
* I switched to a handshoe mouse. Mice had caused me rsi for years: switching back to one at an external monitor is what precipitated the recent bout. The handshoe is large and comfortable, and you move your shoulder and not your wrist - it basically forces you to. I now have no mouse rsi. Also, I stopped using the scroll wheel, even on the handshoe. Note: if you can't get one or can't afford one, focus on moving the mouse with your shoulder and not your wrist
* I remembered that seven years ago I had typed a million words (really) on a cheap logitech keyboard, the mk320. I saw one in a store, bought it, and instantly found it more comfortable than any fancy ergonomic or mechanical keyboard I had tried. Can't tell you why, but it works.
* a foam roller has been helpful for my back
* the armaid has been extremely helpful for working out forearm tension
So basically a mix of better tooling, more attention to workspace and posture, and a heck of a lot of physical therapy. Had to do a lot of massage at first, but am in maintenance now.
If anyone has small signs of rsi, don't ignore them: they can expand quite a bit, and quickly. I lost a few months work.
I'm glad it happened though. I had low grade rsi for years that I couldn't fix, using a laptop and trackpad. Now, I still can't use that well, but I can use an external monitor pain free.
One final tip: in my experience, things that work show progress fairly quickly. Like, 1-2 attempts. They won't cure it that quick, but you'll usually notice some sort of positive sign.
I say this because there are all manner of treatments that don't really do anything or may not do anything for your particular case. People can end up doing 5-10 sessions of something to no avail and at considerable cost.