Chronic sore throats can be allergic, viral or bacterial in origin. Streptoccocal infection
is the most common bacterial infection and
can cause nasal symptoms too. Common allergens causing these symptoms are pollen, mold, dust, pet dander. High eosinophil counts too can cause these symptoms. Viral flu, infectious mononucleosis etc can cause these problems.
A comprehensive investigation including CBC, throat swab, allergic tests etc is required keeping all the points in mind.
Hope this helps.