I never had luck with the Teflon slider either, but if your shoulders hurt, make sure your machine is at the correct height. Sometimes, with a machine sitting on a table rather than in a cabinet will be too high. Your elbows should ideally bend at a 90 degree angle, and lay flat on the quilting surface. You shouldnt have to hold your arms UP
to reach the quilting surface. I KNOW mine is too high , so I know why my shoulders hurt!