Neck pain is most often caused by an injury, tension, arthritis, or chronic misuse of the neck. But in rare cases neck stiffness may be a sign of bleeding or infection within or around the brain or spinal cord. A stiff neck may be a symptom of one of these serious conditions when it:

• Develops rapidly and occurs along with other symptoms, such as nausea or vomiting, fever, headache, sleepiness, confusion, extreme grouchiness, or a seizure.
• Occurs in the middle of the back of the neck (not to one side or the other) and causes pain when the person tilts the head backward or forward. The person may be unable to move the chin toward the chest, for example.
• Is unexplained (for example, there was no injury and the person did not sleep in an awkward position).

Many serious illnesses can cause a stiff neck. Prompt treatment may help prevent serious complications.