Back pain. Conceptual computer illustration of a human body with highlighted skeleton holding a hand to the lower back. Lower back pain, called lumbago, is very common, and is caused by damage to the muscles and tendons surrounding the spine. Treatment is rest and painkilling drugs. The spine is seen to be composed of a column of small block- like bones (vertebrae). As well as supporting the weight of the head, the weight of the upper body is concentrated by the spine at the point where it joins the pelvis. This puts great pressure on the lower back, unless correct posture is maintained and the muscles are sufficiently exercised.