The first thing I got with memory foam was a pillow as a present. I have had cervical disc and headache problems since injury in 80"s-first good night sleep I had. So I invested in the temperpedic (it was in the mid 1990's so no others available then.) Took some getting use to-is very firm until your own body heat starts to warm it and your weight adjusts to you. A sleep study showed I toss and turn 17 times in an hour before this so I was willing to try anything. I slept better with less pain and the mattress keeps you at your body temp so your joints stay warmed. It mat not work for all but it helped me...and then of course finding sleep apnea and wearing a C-PAP helped me into REM sleep; and a antidepressant (after finding ambien worked) at bedtime kept my FMS (fibromyalgia syndrome) sleep dysfunction at bay as well.
Once these were resolved I had a lot less pain and fatigue with better memory too. Diagnosed 1995