I had wrist/hand pains twice, especially during using mouse, and in both cases, it was my own fault.
The first time, I think, it was because of me over-using AC during the commute. It would blow on my hands, and it struck me as a possible fault one day. After I changed my behavior, the discomfort started to go away in a matter of days, disappearing completely in a week or so.
The second time, it was due to a standing desk at new day-job. I've noticed that I have a bad habit of leaning on my hands when standing at the desk and putting some stress on them. I limited the time I am standing, and I'm more careful about it now.
My point is: watch your body, watch what you're doing, and think what could be affecting you. There is plenty of possible causes, and it's most efficient if you get a good sense of what makes your body hurt. It might be something more medical too, but doesn't have to be.