Why could i suddenly develop muscle spasms?

Many reasons: Muscles in our body contract and relax consciously and unconsciously. A muscle that involuntarily contracts without our consciously willing it is called a "spasm." if the muscle maintains a sustained "spasm", it becomes a cramp, as can be seen with exercise. Overuse, spine problems, posture, fatigue, diminished blood supply, injury and certain diseases can contribute to spasms. See doctor.