The biggest difference maker for me in terms of alleviating repetitive strain was switching from a mouse to a trackball. Something about not having to tense my arm up and move the mouse all over anymore...
I suspect lifting weights already improves this generally, as I have periods of much less pain which coincide with being more active.
If you have a body pain problem, "see if lifting doesn't help" is good advice, but you have to be careful, i.e., don't be a dumb gymbro and load on more weight than you know you can hamdle with good form.