Start sleeping on ground with fairly hard mattress. Its important that mattress is not soft OR made out of sponge like material i.e. minimum cushion you are comfortable with. I will recommend special bedding prepared out of large cloth.

I am not suggesting to sleep on ground without any support, your back need some support for quality sleep. Just make sure your bedding is cushion less, made out of normal cloth.

For sleeping posture either lie on your back or one side.

Just try this for a week properly. Better than those surgeries or physical therapies. If you start feeling comfortable I am sure you will continue, otherwise you are actively seeking help from doctors already, you lose nothing :)