Suggest Medication For Sore Throat And Burning Sensation After Having Oral Sex

hello doctor , I'm a male and had a sexual encounter with a female where I gave her oral sex. I got a soar throat a few days later which pulsated burning and slightly feeling it for three months or more and was tested for everything. Had doctors visits where i explained was only on my right tonsil area and still nothing. I was given antibiotics and nothing changed on multiple visits. Finally it stopped pulsating four months later but i can feel it there on the right side ever so slightly with just a little bother once in a while. I have been tested for hiv, cancer and all the life threatening diseases but if i have to many sweets I can feel it more, my right tonsil hurts more and is always twice as big as the left tonsil. Would like to know what you think if it is an std or anything serious. thank you