Low back pain with left leg pain, from the clinical point of view the most common is lumbar disc herniation sign, you can first judge yourself: first, cough, sneeze, if the lumbar pain, and then string to leg pain, it suggests a possible disc herniation. Second, lying on the bed, do the straight leg elevation test, under normal circumstances can be raised to 70 degrees, if the lift is less than 70 degrees there is pain, then put the foot lower, do the hook foot action, that is, the back of the foot hooked upward, if the pain increases, suggesting that the nerve root of the sciatic nerve in the lumbar region is compressed caused by leg pain, suggesting lumbar disc herniation. Third, you can do hip flexion knee straightening exercise, first lie on the bed, flex the hip and knee 90 degrees each, and then slowly straighten, in the process of straightening if the symptoms of lumbar pain and sciatic nerve pain, it suggests a herniated disc.