////Someone makes up the memes.////

No, in memetics, memes aren't made up. They are like parasites in search of hosts. There are always more memes than there are brains to host them so the memes are in fierce competition--looking for the first advantage to move in and set up shop.

////Someone always makes up (OR dreams up) the stories that becomes myths. I've read Joesph Campbell too.////

Myths aren't made up. They are handed down. As far back as you go, they are always there. It's like asking who was the first person to depict the heavens. We don't know. We've always been doing it. That's why older cultures refer to an Age of Heroes in our ancient past. Someone started it but it was someone far wiser than us who, for whatever reason, are no longer here.