dry cough after open heart surgery is it normal?

First of all I am sorry to hear about this. It must hurt like heck with each cough. The dry cough is due to the meds. You can use a humidifier in your room to help, and enjoy losenges during the day but at night all you can do is keep a water bottle in bed with you to sip on. It is not the operation that is causing it. It is everything else. Good luck to you and congratulations for getting through the operation okay.