Sleep paralysis

have you ever felt awake but unable to move ? unable to breath or thaught that you are going to die while sleeping ? then what you were experienceing was Sleep paralysis. Every person exeprience this once in his life time many people thinks that it somewhat is related to alian abduction or sexaul assault by a ghost. but the question is, is it really ghosts that do this to us or is it some kind of physcological activity of the mind. science says that it happens to people because of exesssive stress . but then the biggest question arises is why do people gets the same dreames like a old woman standing in thier room and staring at them or a shadow people present in thier room. but most friegtening thing is that everything seems so real. science does not have any answer for this that why all the people have the same dreames and that also in all over the world. there is something in this world that causes this thing to us .