Dentists working in the specialized field of functional diagnostics and functional therapy need to bear in mind that different pain symptoms and/or syndromes involving the mouth, jaw, and face often coexist and affect each other. Painful muscle- and joint-related temporomandibular disorders (TMDs), for example, may occur concomitantly with certain types of headaches. A specific case history and evaluation is therefore crucial in these patients. In the case described in this article, the patient presented with dull, pressing bilateral pain in the masseter muscle region and neck muscles that had persisted for about 6 years. In addition, unilateral headaches causing severe pain and occurring several times a day in attacks lasting for a brief period of time to several minutes started in the last several days before presentation. These symptoms were accompanied by eye redness and hypersensitivity to noise and light. The general history, specific history, and clinical examination findings suggested the coexistence of myogenous TMD and cluster headache (CH) of the trigeminal autonomic cephalalgia (TAC) type, as defined by the International Headache Classification. This constellation of diagnoses required an interdisciplinary, multistage treatment approach. The coordinated integration of specialists from four disciplines resulted in satisfactory long-term remission from pain via a combination of pain treatment, physiotherapy, psychotherapy, and dental splint therapy. The appropriate diagnosis and treatment as well as the current literature are discussed in this case study article. Keywords: temporomandibular disorders (TMDs), trigeminal autonomic cephalalgia (TAC), chronic pain