Back Support on Sofas and Armchairs

BackShape is a subtle shape designed to work on firm seat backs like car and office seats. It can't help much on sofas  and armchairs, where the bottom cushion is generally too long, the sofa back is too upright to align with your back, and the support sinks into the upholstery.

For these reasons conventional upholstered furniture is very bad for backs, and should be seen as a key risk.

Generally sofas and armchairs are very difficult to alter to provide back support. However you can try using a sheet of plywood at an angle against the back, in order to shorten the cushion length, open out the hip angle, and provide a solid base for a back support. Then a BackShape may be effective for you, with a cushion under your neck and head.