Sore and swollen legs are most commonly caused by overexertion, mostly seen in people who do not exercise for a long time and suddenly exercise, such as standing, hiking and running for a long time. In order to meet the energy needs of the leg muscles, thus causing glucose, anaerobic glycolysis and resulting in increased secretion of acid, the legs can feel sore and swollen with pain. When this happens, the patient’s symptoms may disappear after 3-5 days of rest. Lumbar disc herniation is common in unilateral legs. The nerve root edema caused by compression of local nerve roots after lumbar disc herniation causes soreness and pain in the leg on its dominant side. Some metabolic diseases, such as diabetes, lower limb vascular lesions resulting in poor blood circulation in the lower limbs will feel sore and swollen legs, accompanied by pain or limping in severe cases. When hypothyroidism is not effectively treated, mucopolysaccharide accumulates in the muscle tissues and causes swelling of the cells, which can cause muscle swelling and pain. In this case, not only the muscles of the lower limbs are sore, but also the muscles of the whole body feel sore and swollen and painful.