If there is ringing in one ear when hiccups are present, and if there is also tinnitus during head movements, consider the possibility that it is caused by a foreign body in the external ear canal. If there is hearing loss in one ear, and the symptoms are relieved when lying down and worsened when standing up, it is possible that this is caused by secretory otitis media. If you do not have these symptoms, but only have unilateral tinnitus when you hiccup or when you swallow, consider that the eustachian tube is open and the sound of tinnitus is present. The eustachian tube is located on both sides of the nasopharynx and has two openings: the eustachian tube pharyngeal opening on the side of the nasopharynx and the eustachian tube tympanic opening on the side of the middle ear. Under normal circumstances, the eustachian tube is closed. When swallowing, burping or singing, the eustachian tube opens and airflow passes through the eustachian tube and enters the tympanic chamber, impacting the eardrum and emitting tinnitus sound. The eustachian tube opens and closes to regulate the middle ear and the balance of air pressure with the outside world.