Tinnitus is a ‘symptom’ and the cause can be varied, but it is often related to activity in, or damage to the auditory system.
The actual mechanism responsible for tinnitus is not yet known. However, we do know that it is a real - not imagined - symptom of something wrong in the auditory or neural system.
Most noticeable are those which damage the auditory system, such as noise exposure - either a single intense event (like a shotgun blast) or long-term exposure either through work (musicians, carpenters, farm workers, pilots) or during recreational activities (shooting, chainsaws, loud music) - the ageing of the auditory system and auditory disorders such as Meniere’s disease.
Other people have no auditory symptoms, with other causes including, temporomandibular joint dysfunction, physical trauma, head and neck injury, general health conditions such as diabetes, psychological stress/trauma and prescription and over-the-counter drugs can cause or exacerbate tinnitus. For others, the cause may remain unknown.