Maybe. Firm mattresses are usually the best choice for people with back pain. Very soft mattresses or waterbeds don’t give the spine enough support. But there are some ways that may help you get the support you need without buying a new mattress.
To support your lower back, you can lie on your side and put a small pillow or rolled up towel just above your waist and a pillow between your knees. If you lie on your back, put a small pillow under your knees. To support your neck, you can try rolling a bath towel and sliding it in the pillowcase, on top of the pillow. This roll supports your neck when you lie on your back or side. (You can also find many neck cushions, neck rolls, and pillows in stores that are made to support your neck.) If you lie on your stomach, situate your pillow so that your neck isn’t craned all the way to one side. Don’t use foam pillows; they tend to be too firm and push against your head, keeping your neck muscles from resting. Feather or softer fill pillows will be more comfortable.