Persistent cough can be lot of things aside from cancer – always needs checking out, not always cancer!

Common (non-infection) causes are smoking, post-nasal drip, as well as underlying health conditions such as asthma and GERD. 

I've no idea what cause of cough was in your case, but very lucky you went and got your cough checked out!

You touched a bit of a nerve as I'm someone who has conditions that cause cough ... only last week I was thinking, what if I had a cancer and they missed it as easy to dismiss cough. Maybe I should ask for a chest x-ray sometime!