My throat has been irritated for over a year now...HELP!?

So my throat has been irritated for literally over a year now. It started off where basically my throat seemed kinda cloggged (like it does before you throat) but clearing it wouldn't help fully, so i would kind of cough lightly, sort of like saying "EH-hm" but with a little cough to it, every few minuets or so. i got so used to it that i would do it throughout the whole day and not even pay attention (although i know it annoyed my friends and family) and that went on for a few months. recently, ive realized it works if i just clear my throat and cough with my mouth shut. I dont know what to do, i went to my school nurse once and she said my throat was very red and irritated and she made me gurgle with salt water and eat cough drops for a couple weeks, but it didnt help! some nights it gets really bad and my throat never seems to unclog, and i cant fall asleep for hours! does anyone know what this is, or what i should do? thanks so much!