Can a rib injury cause pericarditis? I accidently cracked my ribs from falling at work, I was diagnoised with pericarditis. I heard that the cuase of pericarditis is hard to determine, but are these two incidents correlated?

Likely unrelated. Pericarditis is an inflamation of the sack your heart sits in... The pericardial sack. The injury to your rib made the doctors do some studies that showed the inflamation. I doubt a rib fracture caused the pericarditis.
Yes, . Yes, the two events may be related. Pericarditis is inflammation of the tissue sac around the outside of the heart. Ordinarily, there is a small amount of natural lubricating fluid in this sac that allows the heart to beat freely. When the sac becomes inflamed, the fluid can thicken and accumulate leading to chest discomfort. In your case, the fractured ribs could have triggered an inflammatory response in your chest that is involving your pericardium. Pericarditis is treated with anti-inflammatory medications, and typically resolves without serious complication. In some cases, pericarditis can recur and may also be associated with more serious conditions. If your symptoms worsen or do not improve, be sure to tell your doctor.