When I sneeze I get a strange trickling sensation down the back of my head. I also have a feeling of fulness in my head and ears. I do not have a cold nor am I recovering from one. I smoke, like an idiot, and have begun to get a headache in this same area of the back of my head when I do. Of course I am trying very hard to quit smoking. I am worried that I have a brain tumour or something.