Hello, Sore throat with dry cough along with itchiness indicates towards allergic cause and associated bacterial or viral infection of throat which can be triggered by many factors like dust ,pollen etc. Also increased clear mucus production is another indicator of allergy trigger in your system for which antihistamines help. A coexisting long standing sinus infection usually prevails in cases like yours. If you have a fever alongwith, do get a COVID testing done .A proper consultation is required further.