There are many causes of left lateral rib pain, such as trauma, pleurisy, intercostal neuralgia, costochondritis, angina and so on. 1. Trauma: trauma to the left side of the rib cage can cause local bruising, soft tissue contusion, or even fracture, which will cause the phenomenon of left lateral rib pain. 2. Pleurisy: pleurisy can also cause the phenomenon of left lateral rib pain, accompanied by chest tightness, and the pain mainly has tugging pain and stabbing pain. 3. Intercostal neuralgia: Intercostal neuralgia also causes left lateral rib pain, because the intercostal nerves are sent from the cerebral spinal cord to both sides through the intercostal space to the anterior wall of the chest, so neuralgia will lead to the emergence of symptoms. 4. Costochondritis: Viral or bacterial infections or ligament injuries can cause costochondritis, resulting in left lateral rib pain. 5. Angina pectoris: coronary heart disease can cause angina pectoris, angina pectoris mainly belongs to the anterior region of the heart pain, usually manifested as squeezing pain, when the left side of the ribs can be manifested in the slightest hidden pain. There are many reasons for the left lateral rib pain, after the emergence of symptoms in a timely manner to the hospital, after a clear diagnosis to give treatment, do not treat privately, so as not to lead to adverse consequences.