Lower back pain is a common condition that refers to pain or discomfort in the lumbar region of the spine, which is the lower portion of the back between the ribcage and the pelvis. It can range from a mild, dull ache to severe, stabbing pain, and may be acute or chronic. Lower back pain can be caused by a variety of factors, including muscle strains or sprains, herniated discs, arthritis, spinal stenosis, or poor posture.