I had a teacher in college tell me after a day of hunching over my work bench to go home and lay on my back on the bed and dangle my head over the edge for a few minutes to help stretch out the muscles. It helps, but I tend to forget to do it.
I am currently quilting at the wrong height....my quilt top is level with my heart. I can only manage about 10 minutes before the aching makes me quit. It doesn't bother me much to piece at that height, but quilting makes me ache.