Husband has a pain on back of leg calf and when it walk hurts and limp?

See vascular doctor: Your husband may be having intermittent claudication. It is caused by too little blood flow, usually during exercise. Generally affects the blood vessels in the legs. Claudication is a symptom of a disease, most often, peripheral artery disease, a potentially serious but treatable circulation problem in which the vessels that supply blood flow to your legs are narrowed. SMOKING IS A MAJOR CAUSE!!