hi,
I would recommend that you go to a doctor or hospital and get a chest
x ray done, that way it will help narrow down the cause of your
cough significantly. While the chances of being life threatening are relatively small, unless you recently had some kind of accident or have been a heavy smoker for a while now.
So all in all, get an x ray done, from there can figure out the next step.
hope this helped.
Get well.