Are you sewing at the dining room table with a dining chair? Bad move. I had all the same problems. Now my machine is lowered and I have an adjustable chair. I learned this working in an office for 33 years. Work with hands the same level as the elbows and feet flat on the floor, knees and buttocks on the same level. You can use a good folding table with metal legs and have the legs cut down to the right height for you. My folding table is only 26" high! And stretch before, during (frequently) and after sewing. Good luck.