Lower Back Pain in the Morning?

Most of the time, the most common reason for the back pain the OP described is because of weakened abdominal muscles that come with age. The stomach sags outward when sleeping on your side and pulls unevenly on the lower back during the night. This is especially pronounced in older women who have had children.

Common remedies are sleeping with a pillow partially tucked under your stomach to support the sag, sleeping in a recliner to force a back sleeping position, and least often adopted is doing ab crunches regularly to tighten and strengthen the abdominal muscles.