try looking at your diet cut out all dairy products,and alcohol,gargle with salt water,get a tincture called glechoma[ground ivy]it helps to dry sinuses,it is possible you have catarrh draining from your sinuses to your lungs.
try herbal expectorants to clear mucus from your throat and chest,you need to find out what is causing you to cough,you should try a qualified herbal doctor,or a doctor or a homeopathic doctor