Acupuncture needles can have a certain sensation after they are inserted, but few would call it pain.  Unlike hypodermic needles which are used to deliver liquids and have a hollow edge to cut the skin, acupuncture needles are solid and slide through your skins tissue rather than cut it.  Acupuncture needles are also much finer then hypodermic needles.  About 40 acupuncture needles can fit into the tip of one standard 18 gauge hypodermic needle!  Due to the acupuncture needles being so fine and the swiftness of insertion, the pain reflexes on the nerve endings are not even stimulated.  There are some areas of the body that will always be more sensitive including the fingers, toes and palms, but it’s generally nothing more than a quick little prick.  By the time all the needles are inserted, you generally do not feel any of them and are consumed with a sense of calm relaxation.