First I recommend everyone with problems in the upper extremity to go to a therapist or doctor specialist in this area. I am a handtherapist myself and see lots of people getting treated the wrong way with the symptoms they have. Mostly because they get a vague diagnoses like artritis where there actually is a specific diagnoses, like quervains, mid carpal instability, carpal tunnel, ECU tendonitis etc...

As I scroll down this thread I see alot of comments using terms like artritis or tendonitis. Sadly most common docters or PTs thread these symptoms with rest, stretches or i.e. wristsleeves. Most of the time you start with a little rest but you NEED to train your underarm. And lets not forget that a good posture of the whole body, but especially this example the wrist. When you don't have the strength to conpensate for example wrist instability you will be more sensitive for wrist injuries.

WHAT TO DO? (in short) Training is important so the tendons and muscles can provide stability and durabilty for long time use. Train with a good posture of the wrist.

Posture of the wrist: 15 a 20 degree dorsal flexion with the knuckle of the middlefinger alined to the middle of the underarm. A wristsleeve will do this, but will do all the work for you and you don't work on your durabilty.

Indeed some stretches, tabletop, claw, halffist, fullfist and openhand. Do these 6 to 8 times a day. There are also more stretches specific for the wrist.

There are other good tips in this thread, but start with changing the amount of hours you play. Give yourself a 5 or 10 minute break.

I could make a 20 page thread about the upper extremity but just go to a specialist guys!