I had a septoplasty surgery over 2 years ago. Now constantly feel like I need to clear my throats and throats get irritated.

I had my surgery over 2 years ago and my breathing I still great. Clear as it should be. However, I constantly feel like I need to clear my throat. No matter what I do it doesn't help. My doctor said it could be dry mouth do to medication but I do t have dry mouth. My mouth salivates fine. It almost fee like there is a thick mucus that constantly slowly drain in my throats and irritates it. Sometimes I try to clear it so much it ends up getting sore. What in the world is going on? Thanks!