How to get a 4 year old to sleep in his own bed?

Since coming to live with me full time in September, my son has been sleeping in my bed with me. I didn't mind it at first and figured that it was okay since he was dealing with a lot of changes in his life. Being in my bed helped him feel secure.I am starting to want my bed back to myself. We went out and I let him pick his own bedding. We decorated his room the way he wanted. He will play in his room, but he refuses to sleep in there.He will cry, scream, and beg me to sleep in my room. Even putting him on the floor in a sleeping bag doesn't work for him. He hates it.Is there a painless way to get him to sleep in his own room? Thanks. via /r/Parenting http://ift.tt/2j0Ts6j