Interesting - I actually switched to a small keyboard about a year ago because I was getting shoulder pain from my right arm hanging so far to the side so I could work the mouse. The smaller keyboard forces both of my arms closer to my body, and the chronic pain I had in my shoulder for a year or two has disappeared.
I was also hoping the switch would help balance out my shoulders after years of right-hand mousing. It took a few days to get used to, but now I'm basically mouse/trackpad ambidextrous. I'm not sure if it helped my shoulder; I think maybe it did, but too many confounding factors.
I guess it just goes to show our bodies are different and there’s no universal ergonomically optimal solution.
When you had your shoulder pain, was it primarily at the very base of the shoulder blade? That's where it was for me before I moved to a vertical mouse.
“Cowboys in the western United States leave their horses when they die. But never leave their saddles, regardless of how long they need to walk in the desert. Saddles are interfaces that are deeply adapted to our bodies whereas horses are consumable items. It should not be forgotten that computers are consumables nowadays, but keyboards are interfaces that we can use through our lives.”
This resonates with me because I decided that I’d use a laptop-sized keyboard and trackpad for all my computing, even at my desk (which is 95% of the time nowadays.)
The apple magic keyboard 2 (I think?) is nearly exactly the same size, layout, and key throw as the pre-2016 MacBook Pro scissor keyboards… and the Magic Trackpad does all the same gestures, etc.
Which means I can switch to my laptop at any time and not have to re-adjust to different ergonomics, everything’s more or less the same. I just can’t wait for my M1 pro max to ship, because I can’t stand the butterfly keyboard having such a different key throw and I’ll be back to more or less parity again.