Signs and symptoms of a tension headache include:

• Dull, aching head pain
• Sensation of tightness or pressure across your forehead or on the sides and back of your head
• Tenderness on your scalp, neck and shoulder muscles

Tension headaches are divided into two main categories — episodic and chronic.

Episodic tension headaches

Episodic tension headaches can last from 30 minutes to a week. Frequent episodic tension headaches occur less than 15 days a month for at least three months. Frequent episodic tension headaches may become chronic.

Chronic tension headaches

This type of tension headache lasts hours and may be continuous. If your headaches occur 15 or more days a month for at least three months, they're considered chronic.

Tension headaches vs. migraines

Tension headaches can be difficult to distinguish from migraines. Plus, if you have frequent episodic tension headaches, you can also have migraines.

Unlike some forms of migraine, tension headaches usually aren't associated with visual disturbances, nausea or vomiting. Although physical activity typically aggravates migraine pain, it doesn't make tension headache pain worse. An increased sensitivity to either light or sound can occur with a tension headache, but these aren't common symptoms.

The cause of tension headaches is not known. Experts used to think tension headaches stemmed from muscle contractions in the face, neck and scalp, perhaps as a result of heightened emotions, tension or stress. But research suggests muscle contraction isn't the cause.

The most common theory supports a heightened sensitivity to pain in people who have tension headaches. Increased muscle tenderness, a common symptom of tension headaches, may result from a sensitized pain system.

Triggers

Stress is the most commonly reported trigger for tension headaches.

Because tension headaches are so common, their effect on job productivity and overall quality of life is considerable, particularly if they're chronic. The frequent pain may render you unable to attend activities. You might need to stay home from work, or if you do go to your job, your ability to function is impaired.