Does anyone own, or has anyone ever slept on a Sealy Posturpedic Mattress?

So after sleeping on an air mattress for several months (for reasons not worth explaining) I finally (and happilly) invested in a Sealy Posturpedic mattress. I’ve noticed that when i sleep on my back I feel great in the morning, but when i sleep on my stomach or side my back hurts like crazy when i wake up. This really sucks since i am naturally a stomach sleeper.

Do you have to sleep on your back to reap the benefits of a Sealy Posturpedic??