Most common causes of headaches
Lack of sodium
Add two pinches of salt to a glass of water and drink it.
If it doesn’t go away in about 30 minutes, it’s something else.
(Technically: too much CO2)
Tends to happen mostly in the winter.
Open all the windows to create a draft / let clean air inside.
If the headache doesn’t start to improve within 30 minutes, it’s something else.