Hello, I've had this smell of what I call cigarette smoke. It's not exactly that but it's the closest I can describe. This I remember started happening since I was about 12 years old. It is on and off not too often but still there, now that I'm older I started smelling again a few weeks ago. It'll happen about 1 a week from a few minutes to a few hours, I think I made the mistake of googling my symptom and now I can't get brain tumor out of my mind. I went to my doctor and coincidentally I have a sinus infection. He told me that was the problem and didn't seem too worried, what should I do?? I tried telling him I've smelt it before but now it has been a little more active...thanks in advance!!!