Pain only during the activity

Might as well share my story.

I've been playing games on my PC with the mouse and joystick for years. Ever since the beginning of the month, I started to feel pain on my right upper forearm, to the point where the pain started irradiating itself around my thumb whenever I used it. I rested for a few days and the pain disappeared. So I assumed that I was healed and went back to my usual routine.

Cue next week when I started feeling a sharp pain in my right arm alongside tightness around it, followed by a sore feeling in my right upper forearm, the same place from before. I took some Advil and it got better. Then the same thing starts to happen with my left arm two days after.

As for the pain itself: it only shows up when I'm using the PC. Other things, such as washing dishes, carrying heavy stuff, using the phone and so on do not trigger the pain. I assumed it's tendonitis, but there's no swelling or constant pain. There's some general, minor, randomized pains around the arm and generalized tightness on my hands and fingers that moves from time to time, including moving from one arm to another. No signs of tingling or numbness.

Thesr past few days have been a nightmare to me. Fear and worry now dominates my mind. I can't turn the PC on because of fear of pain. I wake up every morning in fear because of my arms.

I don't want to be like this forever. I use my PC to talk with my friends, play games, do my drawing lessons and watch series. I don't want to be forcefully stripped off from the things I like because of my arms.

I scheduled a visit to a doctor. I hope it's just nothing and it's just TMS. I don't want to spend the rest of my days in limbo if it's really physical RSI.

Edit: even though using the phone don't cause the pain, typing on it causes the thumb to tighten a lot, to the point that causes fatigue in my left arm. And I'm typing with the index finger.