On the serious side.............. Is your joystick mounted above elbow level? (for most folks this would be yes, unless they have some sort of modified desk / gaming mount).
As an older gentleman (stop asking how old...

) I moved my joystick and throttle controls to lap level and found that to have reduced much of the strain that I was experiencing.
The first way that I did this was simple and the most comfortable. I took a lap desk that has the padding on the bottom meant to sit your laptop on while in bed. I screw mounted the joystick to it and it rested comfortably in my lap and gave me the appropriate amount of room for movement.