We report a case of myofascial pain syndrome (MPS), manifested as nonodontogenic mandibular molar pain referred from the masseter muscle, relieved by a combination of trigger point injection (TPI) and stellate ganglion block (SGB). The patient was a 32-year-old woman who had experienced cold hypersensitivity in the right third mandibular molar 2 months prior to visiting our department. Subsequently, she had visited a family dentist and undergone pulpectomy under local anesthesia. She eventually visited our clinic because there was no marked change in her symptoms. On the first visit, no tooth abnormality was found and the patient was neither anxious nor depressive. Tender points were found in the right masseter and temporal muscles during muscle palpation. Referred pain radiating to the right mandibular molars was observed when pressure was applied to the central portion of the right masseter muscle. As a result, we diagnosed MPS based on evidence of nonodontogenic tooth pain caused by referred pain from the masseter muscle. We performed TPI with 2% lidocaine hydrochloride to the tender point in the masseter muscle. Although the visual analog scale (VAS) pain score dropped from 97 to 36, complete pain relief was not achieved. The TPI was effective for approximately 7 hrs, after which severe throbbing pain returned. The sustained nature of the tooth pain suggested that it was sympathetic nerve-dependent. Subsequently, we performed SGB, resulting in a reduction in the VAS pain score from 90 to 32. Therefore, we performed another TPI and the VAS pain score dropped to 0. We continued SGB and TPI for the next 3 days and the symptoms disappeared. Thus, a combination of TPI and SGB controlled MPS manifested as masseter muscle-mediated nonodontogenic tooth pain.