You may not think you have to ask why that happens, you may think it is just part of the process. But you should actually be able to sew without pain. The first tip comes from my friend and Orthopedic surgeon, Dr Michael Reid. Dr Reid says to get up and move around often, don’t spend too much time in one position. Move your iron away from your sewing cabinet so you are forced to get up to iron and do the same with the cutting mat. He also says to stretch from time to time, raise your arms way up and lean to the left and lean to the right. Roll your head around carefully to stretch your neck.
Be aware of your posture.
I suggest you use a good supportive chair and be sure it’s at the perfect height so your feet are flat on the floor, from your feet to your knees straight and thighs parallel to the floor. In other words you want your body to resemble a straight back chair. And speaking of straight back, try to sew with your back straight and your head held high. Avoid poor posture and rounding your shoulders and lowering your head over your work. Obviously you have to lower your head a little to see what you are doing, but try if you can to lower your eyes instead for a while to give the back of your neck some relief. Your arms should be straight out from your elbows (parallel to the floor) so they are not angling down or up to the machine. All the motion of moving your arms forward comes from your shoulders. For the typical sewer the surface of your machine should be about 29 ½” from the floor.
If you set your machine on a 29 or 30 inch table (normal height) your arms will have to be angled up because you have to add 3” for the average machine. Everyone who sets their machine on a table is sewing 3” higher than the perfect height for pain free sewing.