Chin quiver??

My son turned 1 month a couple days ago. His jaw still trembles when I lay him down, like the motion of lowering him. And randomly if hes laying down flat. Only lasts a couple seconds and if i touch his chin it stops. I looked it up and it says by 1 to 3 months it should stop but it worries me :( seeing his dr tomorrow so I'll mention it but had anyone asked their dr about it before? Of course Google has horrifying results, says its either fine or due to brain damage. Stupid Google