I can highly recommend a book called _Built to Move_ [0]. It tells you to do a lot of things that many people consider common sense, like walk every day, eat vegetables, sleep 8 hours, etc. However, it also explains _why_ to do these things pretty concisely. The most impactful argument it made to me was you can't counteract sitting for 12 hours a day with any amount of exercise. You have to sit less and move around more.
https://www.pnas.org/doi/10.1073/pnas.1911868117
So... the end-game of ergonomic chairs might be no chair at all.
So the problem with "sitting in chairs specifically" is probably not the chair, but the fact that the chair facilitates longer "sedentary bout lengths". If this is correct, then the commenter suggesting to get up and move every so often is probably on point.
Indeed, it's actually what prompted me to go look over the document.
I remember, as a kid, when out and about and before getting into the habit of sitting in a chair all day every day, I would sit on the floor or on random objects, like stones or tree trunks in the countryside. I wouldn't be able to sit still for long periods of time and would need to at least change positions.
Whereas now, in my "ergonomic chair", I can sit for more than one hour at a time with minimal, if any, changes in position. Ditto for my couch (which wasn't marketed as "ergonomic" in any way).
That being said, I've tried using a computer in other positions, like putting the laptop on a coffee table and squatting or sitting on the floor in front of it, or having it rest on my thies while squatting. It gets tiring very quickly, especially in the shoulders and neck area.
So, in my case, what seems to work best is to get up regularly and walk around the room for a bit.
Two hypotheses:
1. I was just incredibly weak due to being sedentary and even a tiny amount of strength training released enough “get stronger” juice to my system that other muscles also got stronger.
2. Pain is a complex phenomena that relies on our bodies being properly calibrated and lack of any kind of strenuous activity mis-calibrated my pain system.
I’m more inclined toward hypothesis 2. Further life experience has led me to believe that our physical and psychological systems are very much dependent on existing in a specific, narrow milieu to function properly.