Soreness on both sides of the thighs may be caused by physiological factors, muscle sprains on both sides of the thighs, lumbar disc herniation, femoral head necrosis and other factors. 1. Physiological factors: such as excessive exercise, often sedentary, etc., may lead to muscle strain on both sides of the thighs, resulting in the accumulation of lactic acid, thus causing soreness on both sides of the thighs. It is also possible that both sides of the thighs are stimulated by cold for a long time, resulting in local spasms and causing soreness. 2. Muscle sprains on both sides of the thighs: Usually, it is caused by muscle sprains on both sides of the thighs in the process of sports, such as high jumping, long jumping or running, which causes soreness and pain on both sides of the thighs, and it may be accompanied by limited movement of the legs and other manifestations. 3. Herniated lumbar intervertebral discs: If the herniated intervertebral discs cause irritation and compression to the nerve roots on both sides, it may cause soreness on both sides of the legs, and may be accompanied by radiating pain in the lower limbs, intermittent claudication and other manifestations. 4. Necrosis of the femoral head: If bilateral necrosis of the femoral head leads to damage or interruption of the blood supply to the femoral head, it may cause soreness and pain on both sides of the thigh, which may also be accompanied by symptoms such as limitation of hip movement and claudication. Soreness on both sides of the thigh may also be caused by other reasons. If the symptoms are frequent and recurring, or accompanied by other discomforts, it is recommended to go to the hospital as soon as possible to clarify the causes and then give targeted treatment.