Rib pain can be caused by bruised ribs, which can be caused by an abrupt and intense blow to the chest during contact sports. It should be noted that if the pain is specifically on the left side of the rib cage, it could be caused by something more serious, such as chronic myeloproliferative disorder, according to WebMD.
Bruised ribs and pulled muscles are the most common causes for rib cage pain after exercising. According to EXOS, formerly Core Performance, bruised ribs can occur after an intense hit to the chest. Contact sports, like football, basketball and wrestling, can often lead to a bruised rib. Typically, bruised ribs can heal without medical intervention within 3 to 4 weeks. EXOS recommends applying ice to the affected area, or taking over-the-counter pain medicine to reduce the painful effects of the bruised rib.
There are ways to avoid making the pain in the ribs worse. Although, according to EXOS, the best "medicine" for healing ribs is time, there are particular stretching exercises, such as forward or backward lunges, that can help to rehabilitate that area of the body.
If the left-side rib pain is couple with unexplained tiredness, shortness of breath, fever or petechiae (small, flat red blood spots under the skin), it could be a sign of something more serious. In that case, professional medical advice should be sought.