Ordinarily the limbs are kept warm by the blood supply in the arteries. In certain conditions the arteries are very sensitive to cold, and develop spasm. The hands and feet can become cold, and painful. Sometimes bony defects (such as cervical rib) or smoking lead to such sensitivity in the arteries. In many patients no cause can be found. You need to be seen by a vascular surgeon who will evaluate you for medical and surgical ways to relieve your symptoms.