Hi there. I understand that chronic cough can be very irritating and hope I ll be able to help in some way. Firstly since your chest xray and ENT examination seems to be normal your cough could be due to acid reflux and while Zantac(Ranitidine) has not been helpful you can try a slightly stronger medication along with some lifestyle modifications. Medication like Proton Pump Inhibitors like Esomeprazole 40 mg or Pantoprazole 40 mg or Rabeprazole 20 mg - once a day on an empty stomach about 30 min before your breakfast. If it doesn t help you may add Domperidone 30mg along with the above medication. You try this for a week and see how it goes. On top of that drugs like Gaviscon 20 ml about 30 min after a meal will prevent or reduce to a great extent the reflux and may help. Simple salt and warm water gargling 2 times a day may help if you feel a constant irritation in your throat. Lifestyle modifications like Avoiding heavy meals and a gap of about 2-3 hours between supper and bedtime may help. Also you can try a course of Antihistamines like Fexofenadine 120 mg once a day which might help if there is an allergic component to your cough. If you feel it might due to pollution or dust allergy then a face mask while outside might help. Hope this helps and you find relief soon.