why won't my 5 month old sleep at night?

He just turned 5 months and he's up every 2 hours again at night. We have a bedtime routine and nap schedule. He falls asleep on his own and he'll even wake up sometimes and fall back asleep on his own. So he can self soothe. I know he's not hungry every time he's up. He goes 3-4 hours during the day without eating so 2 at night is a bit much. Someone help before I lose my mind! We don't do cry it out.. I feel it'd be pointless now considering he falls asleep on his own. Thanks!