Hello, I recently began hearing a clicking sound in my head. Sounds very odd, I know. However, I am a 63 yr. old guy who is very fit. I am on zero meds. Do not take drugs. Do not smoke . I am 5 -8 and weigh 150 lbs. I drink alcohol socially only. This sound is like one would expect a spark plug from a car engine to sound. It has gone from ocassional to almost all the time now. Whether I am sitting or lying down, it s all the same. When my mind is otherwise occupied, i.e. driving or working, it is hardly noticeable, but still there. What is causing this.?? It is not causing any pain or discomfort, but it is a bloody nuisance!