Cluster Headaches: It's a type of "Trigeminal Autonomic Cephalalgia" which is a Neurological Condition that effects the nerves in the face and ultimately head.. Very painful. Very Rare. For people who are Episodic like me, it'll flare up every so often for weeks at a time hence the term "cluster". There will be multiple excruciating attacks a day. The word "headache" is involved due to the pain that's caused in the head (under the skull) but it is much more than a headache by far..