My grandmother got it and she never used any kind of keyboard in her life. I learned one thing from her that has basically cut all of my pain.
When we sleep, most of us curl our arms and hands in. As we move around we sometimes bend them a little too far or put them in a weird position. this puts the joints in a kind of long term, stress position. It's not much, but night after night it adds up. I make a point of always trying to keep my wrists straight.
If my wrists are bothering me anyway, I use wrist braces. The thing with the braces is to use the kinds with the metal pieces in them, but put them on loosely so they don't restrict bloodflow. One or two nights with the braces and my wrists always feel better again.