I have a very harsh, semi dry cough that feels like I have swallowed something the wrong way. The minimal amount of mucus I try to get out, without my toe nails , is very olive green to dark green. It also tastes toxic,like burning rubber. My GP said I had a virus and there were no other tests done to say otherwise, and no medication that would help clear things up. My concern is the burning rubber taste and the very deep coughing fits , usually at night. I had a chest and throat xray 6 months ago for reflux but nothing sinister showed up. I am making an appointment to see another GP and will ask for a referal to a specialist. What is causing the toxic/burning rubber taste?