Back pain is often the result of injuries, which may be acute or occur over time. They include:

• Sprains. When ligaments in the back are torn, usually from a sudden injury, the result can be pain. The pain of a sprain can be severe, localized to one spot in the back or more generalized all of your back and in nearby areas of the body.

• Spasms. Sometimes overworked muscles of the back (and elsewhere) go into spasm – painful, involuntary contraction, similar to a charley horse (a cramp, usually occurring in the calf muscle). While spasms are painful, they are the body's way of protecting itself from the underlying problem. When muscles are in spasm, they become painful and rigid, so that you are temporarily unable to use or damage them further.

• Ruptured or herniated discs.  When discs are weakened, the hard outer covering can rupture, allowing the squishy center to bulge out causing pressure and irritation to nearby nerves.

Learn about herniated discs and their treatment from the American Academy of Orthopaedic Surgeons.

• Vertebral fractures. Fractures of the vertebra may be caused by a trauma, but more often are the result of osteoporosis, which weakens the vertebrae and causes them to crumble. These are called compression fractures.