What Causes Abnormal Sensation In Head?

The past couple of months I have noticed a strange sensation in my head. It is a light clicking that I can hear internally and feel, located slightly to the right of the center of the top of my head. The only time I really notice it is when i m walking; it clicks with each upward motion in my gait. I can also feel it if I just bob my head up and down. The click doesn t hurt, but it is annoying and has me slightly worried.