I have had C-Scans MRI's of hte the chest, throat, sinus. My MD insists that Atenolol does not cause a cough since it is a beta blocker and that only ace inhibitors cause coughs. I have also been on Lopresser and have had the same cough. It is worse in the morning but at times it is a 20 minute hacking cough at different times of the day.
Do you smoke? I had the same problem when I smoked, I've been taking Atenolol for many years. The only thing that helped was an antacid. Prevacid worked real well. I quit smoking about a year ago, and have never had the problem since.