leeneia...It need not be hard on the hand. With some basic technique coaching it won't be. Any physical activity (even the ones using small muscles in the hand) requires rest, but excessive muscle tension, arm/wrist/finger postures which are held at awkward angles, will hurt. Relax the digits/wrist/arm, hold rather than squeeze the pick, don't clench the hand or hold it open beyond its rest posture, relax the shoulders, and let the hand be free of top and bridge.

Pick strokes which have an ever so slight "circular" path instead of "back and forth" helps a bit to, so that muscles aren't stopping and starting continually. (Roy Buchanan was a master of this and was the first one I know of writing about it, though likely it's what good players have done for centuries.)

Peace, Mooh.