Pain two days after rib fracture may be caused by inflammation, movement of ribs due to activity, and compression of nerves. 1. inflammation: because after rib fracture, there will be localized aseptic inflammation, and the inflammation will lead to oozing, which will lead to the symptom of pain after two days after rib fracture. 2. Activity leading to rib movement: because the ribs have been in constant motion, so in the process of breathing, the bone will produce a certain displacement, such movement will cause pain, if it is a deep breath, or coughing, will aggravate the pain. 3. Compression of nerves: Because there are many nerve endings near the ribs, inflammation will lead to swelling and oozing, which will compress the nerves and lead to pain. If the symptoms of pain two days after a rib fracture persist without relief, you need to seek medical treatment.