The most common causes of left lower back pain are lumbar muscle strain, lumbar dorsal muscular fasciitis, lumbar intervertebral disc herniation, kidney stones, etc. If the symptoms persist, it is recommended to seek medical treatment in time. 1. Lumbar muscle strain: If you are engaged in heavy physical labor for a long time, it is easy to cause chronic strain of the lumbar muscles, and if the environmental temperature is low, the left lower back will be easily irritated by the cold and pain. 2. Lumbar dorsal fasciitis: due to trauma, strain and other causes of aseptic inflammation of the lumbar dorsal muscles, when the inflammation attack will appear left lower back pain. 3. Herniated lumbar intervertebral disc: when the herniated intervertebral disc presses on the nerves and the surrounding soft tissues, pain in the lower back and back will occur. 4. Kidney stones: If there is a kidney stone on the left side, it may cause left lower back pain if it irritates the surrounding mucous membranes. The causes of left lower back pain are many, and may also be related to osteoporosis, ureteral stones, fatigue fracture and other reasons, it is recommended to go to the hospital in time to identify the cause of the disease, targeted treatment.