Causes of Back Muscle Spasms Video. A muscle spasm is the body's method of protecting injured structures, or as a means to protect itself from injury. Muscle spasms in the back can be caused by a muscle strain, a sprained muscle, or an underlying condition. 1  Tweet.2  Print.n treating back muscle spasms, it is very important to diagnose the underlying problem. The treatment should be directed at the underlying problem. Unless the underlying problem is evaluated, discovered, and treated, the back muscle spasms will tend to recur.