What Causes A Persistent Sore Throat, Post-nasal Drip, Voice Changes And Occasional Feeling Like Cuts In My Throat And Ear Pain?

Hi, around five months ago I performed oral on someone I dont know very well. The next day I woke up with an extremely sore throat and post nasal drip. i went and got tested for chlamydia and strep throat and both came back negative. However these symptoms still persist and the symptoms come and go frequently. One day I will be fine the next feels like cuts in my throat and pain in my ears. it also feels as though this has affected my voice as it seems my voice is scratchy and not as loud as i once could talk normally.This never happened before giving oral so im wondering what it could be? Thank you