As an addendum to your question, you mentioned you pushed out a pin to break the chain and it was on the other side when you assembled it so I assume you reused the same pin. That's a mistake If it's a 7/8-speed or newer chain, that's an invitation to chain failure. Modern narrow chains, with their thinner side plates and riveted pins, must not be rejoined using the same pin. Pushing out a pin removes its riveted end and reams the hole in the side plate larger. Reusing that pin leaves a seriously weakened point. You must push a pin completely out of these chains and rejoin them using either a master link or one of the special joining pins Shimano sells for their chains.