Left ear ringing from swallowing is mainly caused by abnormal function of the eustachian tube, which opens in the nasopharynx and the inner mouth opens in the middle ear cavity. When the eustachian tube is abnormal, swallowing causes pressure changes in the pharyngeal cavity, which causes pressure changes in the middle ear cavity, resulting in ringing in the ear or a sound of running water. When this happens, you can pinch and puff your nose to open the eustachian tube, balance the pressure in the middle ear, and reduce the symptoms of ringing in the ears. If the pinching and puffing is not effective, you can visit an ENT clinic and have the eustachian tube blown open. You should also avoid blowing your nose hard to avoid retrograde infection through the eustachian tube to the middle ear cavity, which can lead to fluid accumulation in the middle ear cavity.