What Causes Irritation Along With Mucus In Throat Despite Taking Antibiotics?

My throat is aggravating me because it is irritable. Also, there is a little bit of mucus. It has been like this for several months. My doctor gave me antibiotics, then loratadine. Also, I have been using cough syrup and throat drops. I also did ultrasound and xray, but everything seems fine. Just fed up and don't know what to do. Please advise accordingly.