I want to know what is the difference between restless leg syndrome & pad--peripheral artery disease?

Great difference! First, both can co-exist! however, blockage of the arteries in pad, is the cause of pain, usually brought on by extertion and much more rapid build up of lactic acid. Restless lef syndrome occurs without exertion, usually at night. Pad is associated with smoking, bad cholesterol profile, diabetes, and hypertension, while restless leg syndrome is independent of these vascular disease factors!