Thanks for the link. Ergonomics was beaten into me in secretarial school in the olden days, and the exercises to relieve the kinks when they started up. Those positions and exercises have helped me greatly through the years.
Someone mentioned their shoulders just killed them. Try a higher chair, so you arms are somewhat hanging down. This stops you from strunching up your shoulders. If you start getting that pain spot in your neck. Stop sewing. Chin up, move your head to look over your right shoulder and give things a stretch, then to look over your left shoulder and give things a stretch, then (do the chicken stretch) with your head facing forward and your shoulders still stick your chin forward -- same movement a chicken makes with their head when they are walking around. Short chin stick outs forward. Repeat all three a couple of times. If you do that every half hour or so, and have your work at a good comfortable height, it will really help the sore shoulders.