I'm really worried because for almost two years now, it feels like a lot of mucus is just building up in my mouth and throat, and it's like I constantly have to clear my throat. But lately, the past month or so, I've been feeling this burning sensation down my throat, especially when I breathe, and it's super bothersome. My throat and chest also feel really congested. I haven't had a fever, but it's been going on for so long now. What could be causing this?

ENT opinion is advised to the patient.