Left leg soreness right leg normal can be caused by long-term poor posture, lumbar disc herniation, left lower extremity vascular disease. 1. Long-term poor posture: prolonged sitting and standing, walking for a long time, etc. will cause excessive fatigue of the leg muscles, poor local blood circulation, increased lactic acid formation, accumulation, causing soreness. If the left leg is the main affected part, it will be manifested as left leg pain and right leg is normal. 2. Lumbar intervertebral disc herniation: caused by intervertebral disc compressing spinal nerve root and dural sac, if the nucleus pulposus of the herniated intervertebral disc is biased to the left side, then it will cause the left leg’s soreness, weakness, numbness, and so on. 3. Left lower extremity vascular disease: mainly including lower extremity varicose veins, lower extremity venous thrombosis and other diseases, resulting in poor local blood circulation, left leg pain. There are many reasons that cause left leg pain and right leg normal, left leg pain and right leg normal, it is recommended to consult a doctor in time, under the guidance of the doctor, combined with the relevant examination to clarify the cause of the cause of treatment, so as to avoid delaying the condition.