I get this as one of a long list of symptoms stemming from heavy metal intoxication but you may also discover, if you observe your diet very carefully, that certain foods exacerbate the problem.
It's due to fluid in the inner ear, sometimes causing something known as 'hyperacoustics'
Some foods which, in some people, may exacerbate the symptoms you describe include black pepper, dairy foods, oats, yeasty foods etc.