A muscle spasm is a muscle spasm that suddenly becomes uncontrollably tight. This phenomenon occurs when the muscle is under constant tension for a long time, dehydration, and electrolyte imbalance. Muscle spasms are often sudden, short-lived, and painful for the patient.

When you have a mild headache or toothache, over-the-counter pain relievers are often enough to make you feel better. But if your pain is more severe, like cancer pain, your doctor may recommend CNS pain relievers.