English word headache comes from Old English (ca. 450-1100) hēafodeċe

Detailed word origin of headache

Dictionary entry	Language	Definition
hēafodeċe	Old English (ca. 450-1100) (ang)
hevedeche	Middle English (1100-1500) (enm)
headache	English (eng)	(figurative) A nuisance or unpleasant problem.. A pain or ache in the head.