What Is The Cure For Dry Persistent Cough, Itchy Throat ?

i am having a dry cough and itchy throat from last 4 weeks. i had consulted a doctor and took medication. there was some relief but now again the same problem. cough is very irritating, breathing is difficult results in vomiting if occurs after taking food. my age is 22, male , 5 7, 60kg i had never had such dry cough before, but wet cough and cold is commonly happens to me. but cough syrups are relieving but now. no cough syrups are working.