Had cough since 4 to 5 years. Help me!

My self orthodontist .. i have cough since 4 to 5 years... but in x rays and blood report evry thing is normal.. i had gastritis and oesophagieties and gerd 7 years back .. i feel like continues throat irritation and burning sensation due to that i got cough ( khassi ) but when im concentrationg on pateint or any thing it doesnt come and in morning also it is less. i have shown all tge types of doctor all od them hv diffrnt openion .. finish their medicine courses also but no cure.. some says allergy but ige test is also normal.. i dnt what the diagnosis is and bow to whom i should show.. please help me regarding this.. feel like continues throat irritation and burning sensation aftr coughing fr sometime i feel good thn again it comes..