Hi tgrafix,
Some of the better options and possibilities I’m aware of in your general area are listed in post #2 here.
Keeping your spine and joints in their neutral alignment in all your sleeping positions is one of the two main functions of every mattress and one of the most important parts of PPP (Posture and alignment, Pressure relief, and Personal preferences). While it’s arguably the most important part, it becomes particularly important when there are preexisting issues.
The tutorial post includes some links and guidelines that can help you test a mattress for PPP that may be helpful.
A suitable pillow is also part of your “sleeping system” and can also play an important role in upper body alignment and pressure on the shoulders as well so it can be important to make sure you are using a suitable pillow when you test mattresses.
Phoenix