Headache is one of the most complex and demanding areas of clinical practice. The challenge is to understand the pathophysiology, achieve an accurate diagnosis, and offer useful remedies. Headache and facial pain are two of the most common medical complains of mankind.Pain management is not part of the routine training for most physicians, yet the majority of patients seek medical attention because they have pain. Pain is typically addressed by primary care practitioners on an acute, time-limited basis, but when first- and second-level strategies fail, patients are referred to pain specialists and/or disease or body system specialists for more thorough evaluation and management.Pain is a subjective experience, which cannot be easily measured. It requires consciousness. Describing pain as an ‘experience’ separates pain from ‘nociception’. Nociception is the neural process involving the transduction and transmission of a noxious stimulus to the brain via a pain pathway. Pain is the result of a complex interplay between signaling systems, modulation from higher centres and the unique perception of the individual.In order to know anatomy and physiology of headache and facial pain, we should know pain pathway, peripheral and central sensitization and descending pain mechanisms. Also we should know definitions of pain, allodynia, hyperalgesia, dysaethesia and hyperpathia.There are well-defined headache disorders that vary in incidence, prevalence and duration. These disorders are usually divided into two broad.