I had a very similar experience. It started to happen within less than a year of starting my career. Both arms bothered me if I was typing in high gear for a long time, but the right was a lot worse and started to be an everyday thing. I switched the mouse from right to left side for a week and the right side started to feel a lot better. I ditched the mouse for a trackpad and picked up a kinesis advantage and never looked back. Still use a mouse and traditional keyboard layout for my gaming PC though.