I'm 5'8'' and my stool-chair is about 25 inches high and after sitting low for about a year, all my back pain/shoulder pain has left. There's something about having one leg up on the rungs and one on the floor when you're sitting on a higher chair that you can feel your whole pelvis at an angle. I bet that would be the only time when our pelvis is unnaturally angled like that for even a short while.
