Because they allow for a large range of motion, and because they carry so much weight, the ligaments and muscles of your lower back are particularly vulnerable to sprains and strains. Sprains and strains are the most common causes of back pain. Sprains happen if ligaments are overstretched or torn off their attachments. Strains occur when muscles are ripped or torn. Although they usually get better on their own in 1-3 weeks, sprains and strains can be extremely painful, especially if a muscle goes into spasm. The most frequent causes of lower back pain from sprain or strain are lifting a heavy object, lifting while twisting, making a sudden movement, or falling. Although muscle and ligament injury can result from a sudden injury, in many cases these occurrences are not the real cause of the sprain or strain. Gradual overuse, or sitting, standing, or lifting improperly for some time, predispose the muscle or ligament to damage.