What Can Cause Jerking Mediated Bone Click While On Plaster Cast?

My left broken wrist is on plaster cast, and when I am jerking, the bone felt click. Do u know why. Another question, during re position the bone, the gp at the emergency said it is not aligned yet, and she is going to talk to orthopaedic, later on, they discharge me saying I need to comeback to see orthopaedic in four days. If it is not align why they discharge me as the general practice said she may need to re position it. Thanks