Over the years I’ve had a lot of hand and arm problems from using a keyboard too much. For the last couple of years, though, I’ve been pain-free and twitch-free. (There was an extended time when my little fingers and thumbs spasmed annoyingly day and night.)
There are lots of different kinds of keyboarding injuries, and lots of different solutions to them. I’ve changed my chair, my keyboard, my keyboard layout, my desk height, and so on.