I Have Been Coughing For Many Weeks I Have Been

I have been coughing for many weeks I have been sent for x-rays and no chest infection. some 2 months on the cough has still not cleared. I can go for hours without coughing and at other times I am coughing almost all the time to the point of almost choking. It is a dry cough which sometimes gives me a sore throat. your suggestion as what I can do to clear this would be helpful.