A headache was a pain focused within an individual's head. In the proximity of droids, members of the sentient Gotal species could experience fierce headaches, as their conical horns made them sensitive to electromagnetic fields. Humans could also experience headaches, and Karr Nuq Sin did when using his psychometry powers. Anger could trigger headaches; during an intense argument with Ransolm Casterfo, Leia Organa got a headache that made her temples throb. Chiss sky-walkers could experience headaches, known as an overload spell, which could turn severe.
The behavioral modification biochips implanted in the clone troopers to ensure their obedience to Order 66 could cause headaches when malfunctioning: Tup of the 501st Legion complained of a headache just before his chip malfunctioned during the Battle of Ringo Vinda, causing him to kill Jedi General Tiplar. After the formation of the Galactic Empire, the genetically defective clone Wrecker began suffering increasingly severe inhibitor chip-related headaches after sustaining a series of head injuries.