'Mystery' Ear Problem

I have had a problem with my left ear for what seems to be a lifetime. In short, what happens is that any loud noise close by will produce a momentary reaction inside the ear, as if a piece of the ear's 'machinery' is loose and rattles in response. This does not happen if I cover the ear and it does not happen with the right ear. Is it more than coincidental then that I have a mild hissing in this left ear?

Repeated visits to various doctors & ENT specialists have proved inconclusive (& expensive) and examinations including an MRI scan didn't show up anything else.

I wouldn't consider myself to have even remotely the same level of discomfort that others are enduring although it does get worse at times of stress. I do believe that a cure will be found some day, once the exact nature of the problem has been identified.