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).
At first it is mildly sensitive to cold. Then it becomes progressively more sensitive to cold. It may become so that the toothache pain is even spontaneous. The final stage before the pulp of the tooth dies is that the tooth becomes sensitive to heat and cold actually relieves the pain. This is a case of acute pulpitis. The pulp of the tooth is nearly dead, and will need a root canal. Click here to read more about root canal treatment.