I've been battling a nagging AC joint issue for awhile so I know your pain (figuratively). My approach to alleviate this was simple: if it hurts, don't do it. I quit doing pressing movements that hurt and used cables and DBs to work the involved muscles. Unless you're training for a lifting competition then you can do the same. Cable Fly's of all angles didn't bother me so I did those on chest days. Lateral raises covered my delts on days that overhead pressing hurt.
Lastly, a technique cue. Make sure you pull your shoulder blades back (retracted) and down (depressed) and lock them in position when you do your bench and incline movements. It provides the best surface angle possible for the head of your humerus (upper arm) to contact the glenoid fossa (shoulder blade) thus reducing stress on the joint.