What causes headaches?

Varies: If due to brain tumor or hydrocephalus, cause is increased intracranial pressure. If due to migraine or medication reactions, this is likely affecting brain glutamate which triggers hypersensitivity to stimuli and a headache. Stress may cause a tension headache, but jaw problems may also trigger. Some foods, like nitrites, msg, red wines, pickled herring can trigger migraine.

Take your pick!: Brain tumor, sinusitis, multi-infarct dementia, transient ischemic attack, temporal arteritis, subarachnoid hemorrhage, lead poisoning, paresthesia, tmj, abcessed tooth or teeth, cracked tooth, eye strain, etc. In short, do not self diagnose, seek professional help as pain is usually a sign your body needs help. Most importantly, make sure the final diagnosis makes sense to you!