-- Question: What Should I Consider When Selecting A Bed If I Have Low Back Pain?
Answer: The reality is there's no one best firmness or type of mattress for everyone.
Firmer mattresses can provide additional support, but sometimes they do not keep your spine in the proper alignment, and may cause increase in your pain symptoms. Softer mattresses tend to provide less support, and may cause your muscles to work harder at night.
In studies looking at this very question, they found that medium firmness mattresses probably provided that best support for the majority of patients with low back problems.