Soreness in one leg and nothing in the other may be due to physiological reasons such as overwork, or it may be caused by lumbar spine disease, hip joint disease, lower limb vascular disease and other reasons. 1. Physiological reasons: due to improper exercise or over-exertion, it can cause over-exertion of the muscles of one leg and accumulation of lactic acid in the body, which leads to one leg soreness and pain. 2. Lumbar spine diseases: such as lumbar spine tuberculosis, lumbar spine tumor, lumbar intervertebral disc herniation and other diseases compressing the nerve root on one side, the patient may have one leg pain and numbness symptoms. 3. Hip joint disease: one side of the hip joint femoral head necrosis or hip arthritis and other diseases, may appear on the affected side of the limb pain. 4. Lower extremity vascular diseases: commonly seen in lower extremity varicose veins and other diseases, due to the lower extremity venous blood stasis, local swelling, the patient may appear on the affected side of the limb pain and swelling. One leg pain and the other is fine there may be other causes, it is recommended to consult a doctor in a timely manner, with the help of a doctor to clarify the cause of the disease, and targeted treatment or treatment.