Why does my dog get nervous when I try to move him to the side of my bed that's against the wall?

Sometimes when my dog is laying in the middle of the bed, and is in the way for me to sleep, I’ll try and move him over. My bed is in the corner of my bedroom. For some reason he gets quite scared and he’ll put his brakes on and jump away from the wall. I don’t really understand; it’s not as if he is going to fall off the bed, hit the wall, or even fall through. There is not even space between the bed and the wall. Does anyone else’s dog do this? So strange.