First, lumbar spine disease. This is the most common cause of pain in the lower extremities, especially with numbness. This pain tends to appear in the outer thighs, sometimes on one side and sometimes on both sides. This pain is relieved from time to time and is often not accompanied by chills, but not absolutely, and is often accompanied by pain in the lower back. Second, pain caused by diabetic peripheral neuropathy. This pain is also often accompanied by numbness and coldness in the lower extremities, but the pain and numbness are mainly in the feet, and often accompanied by dullness of sensation in the feet. If you have been diabetic for seven or eight years, nine times out of ten, you will develop this disease. Third, osteoarthritis of the knee. Almost everybody gets this disease. I see it almost every time I go out to the clinic. It is usually in the elderly, and most of the pain and chills occur around the knee, sometimes on one side, sometimes on both sides, and in severe cases you cannot walk. A film is taken for a preliminary diagnosis. Fourth, occlusive atherosclerosis. This is also known as narrowing or occlusion of blood vessels, and is more common in the elderly. If your dorsalis pedis artery pulsation is not touched, you should come to the hospital for examination. Fifth, acute deep vein thrombosis of the lower extremity. This kind of pain, often accompanied by swelling, usually without chills, will be severe with chills and numbness, then it is serious. There are also all kinds of infectious diseases, such as lower limb dermatitis, cellulitis, etc., which are also common. There are many causes of cold and pain in the lower limbs, and when they occur, they must be taken seriously.