Obus Forme is a company that actually has a long and successful history in designing equipment that is good for backs.
These have a good research base in theory and in actual user results. If you have a sore back, this may be the route you want to take. The system looks at the total back and aims to begin with a neutral posture in the pelvis, moving up through the lower and middle back, and positioning the shoulders into their most functional posture.
Obus Forme Backrest and Seat