Chest hurts extremely when I cough?

Just a couple of months ago I broke my sternum. I was always working out, or in a sport so it didn't get the proper recovery it should have. (For all I know it's still broken). I started to get a very bad cough about a week ago. I've had the cough before but it soon went away but now it's back and worse than before. A feeling of throwing up occurs every time I cough, along with excruciating pain in my chest. Is the pain in my chest caused from the cough? Or could I have done something to my sternum again?