A memory foam mattress topper can be good for your back. Of course, it depends on the source of the pain and the type of mattress used under the mattress topper. Back pain caused by a sagging mattress, for example, won’t go away with a topper because the topper will sag, too. However, pain that stems from a lack of cushioning can certainly be helped by memory foam. You can also buy firm or zoned memory foam mattress toppers that offer more back support.