Hello There, You need to visit to Physician for thorough clinical examination, because as per your history, problem is since 1 year. Clinical examination and personal Review with physician is must. It might be just a allergic cough or Asthmatic cough. To dignose this problem some information is mandatory, like Duration of cough; consistency of Cough, color of sputum; Frequency of Cough; History of Smoking; any accompanied symptoms. So all these points should be discuss with Physician personally. Some dignostic tests may be required like Chest Xray and  Sputum culture sensitivity.