TJ Isn't Sleeping

I don't know why but he doesn't seem to want to sleep lately. He wakes up multiple times a night and it is getting exhausting. More so for Sue than me, but I'm still tired too. But if we sit in the reclining chair in his room and leave him in the crib, he's okay with that and he'll go back to sleep. Is he scared? Is he lonely? Is he just trying to drive us crazy? Could be all 3, I just don't know.