For me, I've been using a smaller keyboard (60%) and hardly use the mouse so I don't need to move a great distance with my arms.
I try to keep my desk height and monitor height OK as well.
More for preventation rather than for 'curing' anything. Though I sometimes ponder wether or not I should also just get an ergonomic mouse for the times that I do use it. :)
I have back pain from a muscle injury. I use a small wireless keyboard in my lap. That way my arms rest naturally and my elbows are touching my sides, as if you sat naturally with your hands resting on your legs. This way I avoid using my back muscles which happens when you move your elbows or arms outward. The typical office position with arms outstretched and sometimes resting on chair arm supports actually strains back muscles.
Not saying it is perfect but they probably know more about it than I do xD