I sleep with earrings in every night, ranging from diamond studs, to sterling silver barbells and a pair of pearl earrings (I actually found them inside of a clam that I had picked up off the beach and there were two pearls inside. So they became earrings.)
I have 10 holes in my ears, 5 in each, and am also a side sleeper. But I've never had a problem with any of them.