I'd go to a doctor and maybe have them take a swab and sample from inside your nose to test for infection. It may be a sinus infection, or something stuck up there. My mom as a child put cotton from a stuffed toy up her nose, and it began to smell the air up around her. The doctor looked up her nose, saw the material and pulled it out. If its just a sinus infection than strong antibiotics may help. I had a sinus infection and had to take two very strong rounds of antibiotics to get rid of it.