Hairstyle dictionary: "Having painful hair"

Having painful hair
 
The myth: The expression means that your hair can be painful and thus make you suffer. However, this is not possible because hair does not have nerve endings.
 
What it really means: The phrase "painful hair" is a roundabout and elegant manner of saying you drank too much the night before and you have a headache today. In this situation, the hair is associated to the head meaning the painful hair is actually a headache driven by excessive alcohol consumption. The most common equivalent expression is "Having a hangover."