The causes of soreness in both legs are arthritis, lumbar disc herniation, varicose veins of the lower limbs and so on. 1. Arthritis: due to strenuous exercise, overloaded work, long-term standing and other factors, resulting in aseptic inflammation of the joints of the patient’s lower limbs, there is an exudation of inflammatory substances, constantly stimulating the surrounding muscles, resulting in patients with soreness in the lower limbs. 2. Lumbar disc herniation: If the patient suffers from lumbar disc herniation, it may cause the nerves of the legs to be compressed, resulting in the muscles of the lower limbs being in a state of tension for a long time, which leads to the symptoms of soreness and pain in the lower limbs. 3. Varicose veins of the lower limbs: due to the obstruction of the function of the venous valves of the deep veins of the lower limbs, the blood circulation in the veins of the lower limbs is impaired, so that the pressure inside the veins is increased, resulting in the infiltration of fluids and their accumulation in the interstitial space of the tissues, which leads to soreness in the lower limbs of the patients. There are many reasons for patients to have soreness in both legs, it is recommended that patients go to the hospital in time to improve the relevant examination, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.