My DS was doing this, it was really draining and would last for up to two long hours of growling, begging, bribing etc and he still wouldn't stay in.

Now what I do is sit in there with him until he is asleep. It usually takes about 20 minutes, a bit of a pain but a lot better than what we had. The idea is to gradually move away from the bed and eventually out the door, or to start going out for little jobs eg just have to go to the toilet/check on the baby etc until he will go to sleep by himself.

Good luck, I feel your pain.