One of the main causes of sinus drainage is simply being alive. Every day the human body produces several liters of sinus fluid and mucus, and all of that natural liquid must go somewhere.
It is a area of tenderness of the scalp in which people also sometimes feel stabbing headaches. Others just feel very sore and tender to the touch. It is felt to be caused by irritation of the connective tissue which attaches the muscles of the scalp to the skull (cranium).
Massage a clarifying shampoo into your scalp using the pads of your fingertips. Using fingernails on your scalp can cause scratching that causes your scalp to produce more oil. A clarifying shampoo can help to remove dirt and sebum buildup from your scalp, but should only be used once per week unless otherwise directed.