I've gamed my whole life, I don't have carpal tunnel syndrome. There are other factors that can lead to it, your body with how large your carpal tunnel canal is, some medical conditions can inflame the tendons in the area squeezing the nerve. I wish I could help with how to play, hopefully this is something that's reversible if it is just a carpal Tunnel issue, but if there is more it can be more complicated. I feel for you, I can't imagine not being able to do what I love. Good luck.
Swelling and pain isn't CTS, you are doing something to your muscles. CTS is numbness and tingling on your fingers and hand. At severe levels you will have weakness, the feeling may radiate up your arm as a dull ache. But it isn't mechanical wrist pain.
There are ways to help prevent CTS but like I said above there are sometimes factors that are out of your control. Repetitive wrist motion can cause it, people on computers, hair dressers, and so on develop CTS more than other professions. Wearing wrist splints at night or even on the job if you can manage it could help.