Tension headaches can be characterized by dull pain accompanied by a tightness or pressure around your forehead and down the back of your head and neck. When a patient suffers from them for less than 15 days out of every month, they are episodic tension headaches, while more frequent attacks would be chronic tension headaches.
A tension headache can last anything from a half hour up to several days. An episodic tension headache is most likely to start off gradually in the middle of the day and build up slowly, while the chronic variety comes and goes over a longer stretch of time.
Tension headaches can be painful, but they do not usually stop someone from going about their daily activities, nor do they cause any visual disturbance or loss of balance. There is no definitive cause for tension headaches, but stress is known to be a trigger.