My veins in my arm hurt after I've been cold. Why does this happen?

There . Must be a misunderstanding of terminology. Veins, and I have no idea what you may call veins, do not hurt. Even when there is a blood clot in them it is the surrounding inflamed tissue(s) that hurt and not the vein itself. In the leg bulging veins may hurt but is distension of the skin that is painful. So I do not have a satisfying response for u. Sorry!