** Thanks for contacting with your health concern 1. As there is a history of physical exertion: i .Think of fractured rib. ii. Think of costochondritis, very common anteriorly iii. Think of muscle sprain. . If by adopting - hot water fomentation - rest with minimal movements - chest strapping - intercostal nerve block - taking an analgesic, anti-inflammatory enzymes, and muscle relaxant, the pain goes away continue with the same, however, if the pain is not relieved ask for Hb%, WBC, ESR & X-ray Chest 2. Apart from injury, pain could be a pleural pathology. [ask for chest X-ray to exclude pleuritis, pleural effusion, since breathing is also causing pain] PS. Although most of the times, pain may be the result of minor injury or postural changes, however sometimes there may be an underlying medical condition/situation which needs appropriate treatment.