I have my machine up high! Put it there because hunching over a lower machine really hurt my upper back and neck and shoulders. My seat is low and my machine high. A side benefit is when I'm doing complex quilting and standing helps me keep the bulk of the fabric in the right place I can do so easily.
I used a ball to sit on while sewing for years after a roll over in an RV and a sacrum injury. It keeps you a bit lighter all around (think it would be different, but....).
Also, we have hand rails on both sides going up to our apartment and I use those to do a stretch a massage therapist told me to do.... put one foot up a few steps, lean forward against that upper leg and push forward and up and around to standing, stretching my chest out as I go. It is a wonderful way to relieve that ache caused by leaning forward so much. You can do the same using a door, but the stairs work better.