As mentioned before this sounds issue with improperly height of sewing or cutting table. Just like when typing your arms should be bent at a angle like a "L" when you working. do a search. There were many good sugesstions about how to adjust your table to adjust to this angle. My DH cut down the legs on my table and then added a peice of double foam insulation on top and dropped my sewing machine into a hole that he cut. That allowed my arms to be at the proper angle and also gave my wrists something to rest on. I saw this method on a UTUBE video. Check under sewing table. I also take frequent breaks when quilting top of quilt. My problem seems to be moving the top around to do the quilting. My arms and shoulder can get really tired doing this. Again frequent breaks and doing shoulder excerses.