A common cross-body shoulder stretch can hurt if you yank your arm across without first retracting your scapula. Set the scapula back into its socket first, then bring the arm across to protect your AC joint and avoid anterior shoulder pain.
This shoulder stretch can make pain worse. Most people, when they do a cross-body adduction stretch, they'll just yank their arm across. This pulls into the AC joint. What you want to do is set the scapula back first, feel it pull into the pocket, then come across. That'll prevent anterior shoulder pain but also still stretch the posterior capsule. Save this for later.
