It's funny that this is mentioned as I have been experiencing pain for the past couple of years, but have only recently focused on it. On Sunday, I had a heating pad on my wrist/thumb. What types of stretching do you do? I work in an office/classroom/at home and am typing on something most of the day. Any recommendations?
The type of stretching I do is holding the base with the left hand while the right hand...HAHAHAHAHA, JKJK!
I've been pretty flexible due to martial arts training and stretching for weight training. I bend my wrists backwards until pass the 90 degree angel on a flat surface about hips level and hold that for 30 seconds while NOT locking my elbows. Then, I stretch the opposite at an angle also on a flat surface. The degrees of the angle you have to experiment with to feel the "pull" of the extensors in your forearms. You have to play with the angle to feel the pulling sensation. Trust me, it feels really good to release all the muscle tension! I repeat about 4 to 5 sets. Remember to only stretch when your body is warm.
Also, get one of the typing pad so you can rest your palms on it so you can type with your wrists in a natural, unbended position. Type for about 30 minutes and rest for 10. Do biceps curl and other pull down exercises strengthening your forearms while NOT moving your wrists ie. wrist curls. Try to keep your wrists in a natural/unbended angle while living your life!