This is more commonly referred to as low back pain, which affects many people. It is chronic, and often precipitated by moving, lifting objects, or twisting of the waist. Bed rest often relieves it. There are many causes for low back pain, ranging from muscle spasm, disc problems, arthritis, to the spread of cancer from distant sites. The treatment also ranges from symptomatic relief with analgesics, to surgery on the lumbar vertebrae.