Ed,
I read your post about an agonizing day chip carving and a backache. You gotta be doing something wrong. IMHO
Chipping is probably the most relaxing form of carving and the only thing that should get sore is your wrist or eyesight.
You need to sit with a chip carver for a few hours or watch a video. Try this sight- My Chip Carving. Its the next best thing to one on one lessons. Relax, keep your blade sharp, elbow in, and most important enjoy yourself. Hope this helps.
Bill K.