Some causes of headaches are alcohol use, loud noise, Eye or Back or Neck strains, emotional stress, depression, changes in sleeping and eating patterns. All of these causes are very common causes of headaches.
But most headaches can commonly happen in blood vessels, muscles, and nerves that cover a person head and neck. They can either tighten or swell or just in general go through changes that stimulate the surrounding nerves or can just enforce pressure on them.
Some common times of the year to get headaches is January, February, July, August, Autumn, and Spring time.
This helped me remind myself of what they taught me in Health class recently, thanks for indirectly reminding me! Hope this helps!