There is no clear-cut explanation of what causes tinnitus, but it is normally found within the hearing mechanism itself. There are many possible causes such as where there are problems with the external and middle ear; i.e. wax, middle ear fluid (glue ear), otosclerosis and chronic infection of the middle ear. These conditions can be treated. Exposure to noise is one of the main causes of tinnitus in the inner ear, where the tiny cells of the cochlea are damaged.