I have had a lot of problems with stiffness in my right wrist from playing the guitar and working on the computer. I was going to yoga, it took me several months to just realize that simple push ups and yoga exercises that put weight on that hand was the main thing I needed to focus on. While all the other yoga stuff was cool, that was really all I needed to spend most of my time on for the most part and it has helped a lot. I tend to do half push ups from being on my knees.
I had also spent a few months going to a personal trainer class once a week to deal with this as well. I ordered books also. The only other thing that helped was getting a better computer desk because I was looking down using the old desk set up and my shoulders were having pain. The personal trainer made the observation about my shoulder.
I was just at the gym and bouncing a 6 pound medicine ball of the floor one handed and alternating each hand. I could feel that that type of movement and exercise was working out some other kind of stiffness in my forearm so I just ordered a 6 pound medicine ball off of amazon. The 8 pounder was ok but the 6 pounder felt like the right one. They used to have a 20 pound ball there but people were throwing too hard on the floor and ruptured it so they no longer have it. That is a two handed thing and I had been using that for a while but since it is gone I was playing around with some of the other smaller balls.