Hey, I had that too. Pains in my forearms, that is, a few things helped:
- try and keep a correct posture. Shoulders should be relaxed, hands forming a little cup in line with the forearm.
- turn the volume up! :lol: I used to play harder than I needed to to get heard
- service your keys, especially if they're weighted.
Some of it, though, is just a normal reaction of your body. After fixing the things above, I was back to normal.
HTH