A build-up of wax and other secretions kept in place deep within the ear by longterm stress.
I'm convinced that, in this modern world, we are unable to relax. None of us fully appreciates how tense we are a lot of the time. So a lot of energy gets clenched in. If we can allow ourselves what is actually a tremendous luxury of relaxing completely for a period of time, the most incredible things can happen emotionally, physically, psychologically. Ten days in that retreat changed my outlook, my body, my life. Epiphanous.