Pain on my ribs?

Many possibilities: Ribs may hurt for many reasons, such as trauma (bumped into something, somebody poked a finger into the ribs), coughing (bad cold & cough symptoms), jogging/running (breathing heavily for a while), weight training or sit-ups (over exertion while exercising), irritation in the rib's bones/muscles/cartilage/linings, a tumor (rare), etc... If symptoms don't go away quickly, one must visit a doctor.