system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What goes on in the brain during a headache?
gpt
Generally, a headache isn't directly in the brain, and there are different kinds of headaches.

  One organ that does hurt during some kinds of headaches is the dura mater which is a tough membrane around the brain that contains the cerebral spinal fluid.  It is well-innervated with pain receptors. 

Other headaches may just be pain in the eye sockets or sinuses.