The low back, also called the lumbar region, is the area of the back that starts below the ribcage. Almost everyone has low back pain at some point in life. It’s one of the top causes of missed work in the U.S. Fortunately, it often gets better on its own. When it doesn't, your doctor may be able to help with several effective treatments.

causes

The most common causes of lower back pain are strain and problems with back structures.
Strained muscles often cause back pain. Strain commonly occurs with incorrect lifting of heavy objects and sudden awkward movements.
Strain can also result from over-activity. An example is the sore feeling and stiffness that occurs after a few hours of yard work or playing a sport.
Vertebrae are the interlocking bones stacked on top of one another that make up the spine. Disks are areas of tissue that cushion the space between each vertebra. Disk injuries are a fairly common cause of back pain.
Sometimes these disks can bulge, herniate, or rupture. Nerves can get compressed when this happens.