I've joined the party of having pain from forehands lol. But for me, RHFH, it's nerve pain in the lower back, 1 inch to the left from the spine/middle. In fact, I rubbed the area, and there's a small bump at that spot. I'm pretty sure it's a lack of follow through. when I RHFH, I use mostly wrist snap, elbow close, and my front leg (left leg) doesn't really move much. So I'm going to try to pivot more on my left heel, and lift my right heel off the ground like sidewinder mentions.
Also before I've usually used a wide stance with lots of weight on my legs. I'll try to narrow my stance and use more upper body vs lower body.
Sidearm is pretty killer on you if you don't do it right, lol. Backhand never seems to be that bad, even if your form isn't perfect.
