It maybe Post nasal Drip-Meaning- Thick Nasal Secretions coming in throat through nose. You need to deal with rhinosinusitis first.
Next Steps
Steam Inhalation with camphor or simple steam will do. You need a proper consultation for same.
Health Tips
Don't clear the secretions repeatedly. Remember More You Clear More the Secretions will come out.DO NOT LET IT UNTREATED. Get proper consultation and please get it treated.