The Real Cause behind Back Pain, Sprains, Strains, and "Slipped Discs": Tiny, almost microscopic rips and tears in the fiber-like ligaments around the discs that bind and connect the bones in your spin are the actual cause of your back pain. The tiny tears become swollen and cause the disc to bulge out, and in severe cases, to irritate the spinal nerves. That causes the pain in your back.
What About Muscle Spasms? Sometimes, to protect the injured area, the muscles go into spasm. Pain is the body's way of actually splinting you-preventing you from twisting and dong further damage.
What Tension's got to do with Back Pain: Tense tight muscles, ligaments that connect joints are more likely to tear. If your muscles and ligaments are tense, like a taut banjo string ready to snap, they have less "give"; if they are flexible, they have the needed elastic "give" for movement and range. Remember, driving is an activity.