Lateral left lumbar pain can be caused by a variety of factors, common lumbar muscle strain, lumbar disc herniation, lumbar trauma and other reasons, as follows. 1. Lumbar muscle strain: Lumbar muscle strain can occur under the influence of many factors, resulting in left lateral lumbar pain. It is mainly due to the long-term repeated excessive lumbar movement, which will change with the weather changes and the degree of exertion, with more factors, such as sedentary, long time engaged in gravity work. 2. Lumbar disc herniation: Lumbar disc herniation can also cause left lateral lumbar pain, the left lumbar spinal nerves are compressed, which leads to the left side of the lumbar pain sensation. Sometimes it is accompanied by other symptoms such as leg pain and numbness. 3. Lumbar trauma: Lumbar trauma is also one of the causes of left lateral lumbar pain. Lumbar muscle and ligament injuries are usually caused by trauma, and in serious cases, bone injuries can also occur, which can lead to localized bruising and edema in the lumbar region, resulting in pain. Other causes of left lateral lumbar pain include kidney and ureteral stones on the left side, herpes zoster in the left lumbar region, and inflammation and tumors in the lower left chest. If necessary, go to the hospital in time for a detailed examination and early standardized treatment in order to avoid causing other diseases.