People with low back pain can find great relief when placing a pillow under their knees while sleeping on their back. This provides support to the hips and low back for resting ease. If you sleep on your side, place a good size pillow between the knees, lower legs and to the ankles as well. This position will keep the hips level & prevent long hours of pull on the low back muscles. Then ALWAYS, ALWAYS sit up from a side lying position to ease into the seated position from the horizontal one. This will help avoid strain to any of the back muscles when you sit up.