Leg stomach muscles do not hurt when lying down, but hurt when standing up may be caused by cold legs, phlebitis, lumbar disc herniation, varicose veins of the lower limbs and other factors. 1. Cold legs: cold legs are a common cause of leg pain, so pay attention to leg warmth, appropriate activities, massage and so on. 2. Phlebitis: It mostly occurs in the lower limbs and is mainly associated with obesity, sedentary lifestyle, less movement and other factors. It is mainly due to the pain in the region of vein travel, and can be localized to appear hard knots. 3. Lumbar intervertebral disc herniation: it is a common clinical disease, which may be related to intervertebral disc degeneration, heredity and other factors. Pain may occur during walking or exercise. 4. Varicose veins of the lower limbs: related to the weak wall of superficial veins, etc., there may be soreness and discomfort in the legs, and the pain will be aggravated in the long time of standing and in the afternoon. After the physiological factors are excluded, you should go to the hospital in time and standardize the treatment under the doctor’s guidance to avoid delaying the condition.