I Have Been Experiencing A Bad Smell At The Back

I have been experiencing a bad smell at the back of my nose and into the back of my throat for a few months. I cannot describe the smell, but it is quite a foul smell and I am becoming a bit frustrated by it happening which can be around 10 - 12 times a day and lasting only a few minutes to 15 - 20 minutes or longer. My nose can be a little bit runny or quite dry and I still get the problem.
My husband assures me he cannot smell anything emanating from me and no one has made a comment to me, so I am hoping that it will stay an internal problem until it can be eradicated for good. Do you have any advice - 58 year old female