Could it be RSI? I get a lot of pain in my right wrist, I can't pout any weight on it and it needs supporting. I work at a desk all day and am right handed and I found that when I had time off work - holidays, bank holiday, sickness, maternity, etc the pain would stop. You can get wrist supports for your wrist and also for your keyboard and mouse if you find this to be the case, you could also try an ergonomic keyboard or mouse.
I was told by my osteopath that a burning sensation is often the first sign of arthritis in a joint and that this sensation often disappears once the joint becomes painful. This is what happened in my case.