will my dog have to have surgery if he dislocated his shoulder, to put it back in

smjauss,

The shoulder joint of the dog is considered to be a fairly weak joint...it doesn't have the ball-and-socket strength of the hip joint or the muscle mass that protects and strengthens the hip joint.  For those reasons, the shoulder joint can be luxated (dislocated). 

Whether or not surgery would be necessary actually would depend on the type of injury and what kind of damage is suspected.  So, the answer to your question is maybe...you need to have an examination of your dog before any of this can be determined.

Helpful Buckeye