I actually had a very similar problem. I was smoking bongs and blunts everyday where it got to he point that I would cough up lougies filled with tar residue as this scared me I decided to opt to purchasing a vaporizer. After 2 months of using only the vaporizer the lougies started to go away and when smoking the vape it would make my throat very dry so it was helping to eliminate mucus that was chilling in my lungs. In your case you could have different issues do you happen to still have your tonsils ?