I have had a cough for about the last 5 years. Can not figure out what the cause is. I have had allergy test and came up with very little (allergic to some roaches and dust mites, but not much else. I usually cough more in the car, and in the evening, during the day when I am up, moving and busy I cough much less. Also, very little if ever during sleep. If I eat or drink something cold it seems to act up almost immediately, and I also choke on food more often that usual. Any ideas what could cause all this coughing?