If the pain is severe, you can do the following actions: 1) Take a deep breath and hold it. 2) If the pain is on the left side, lift the left limb up and stretch it to the right side, while stretching, take a deep breath and hold it for a few seconds. 3) Pat the sides of the chest or the painful area under the ribs, then take a long, slow breath and repeat several times. This will gradually relax the breathing muscles and reduce the pain. At the same time, pay attention to rest, reduce the amount of exercise, you can use hot towels for hot compresses, and oral pain medication for treatment, if the pain is heavy, you need to go to the hospital for examination.