Disclaimer: I'm no M.D., just a rotator cuff tear patient, so I've done a lot of self-research and picked my ortho's brain. A type II acromion process dips down (is downward sloping) and leaves less space for the supraspinatus tendon (lateral rotator cuff muscle) than a type I (most desirable) acromion does, but is better than a type III (least desirable and most curved).
This means that overhead movement carries a higher risk of impingement for you that a person with a type I acromion. As far as degenerative change of the AC joint, it sounds like maybe pre-arthritic acromio-clavicular joint (junction of the collarbone and clavicle).
If there is a small amount of fluid in the sub-acromial space, you may have a partial-thickness rotator cuff tear (usually overcome w/PT); the body will fill these spaces with fluid, leaving a 'clear' impression on the MRI. The glenoid labrum is a cartilaginous triangle-shaped 'pocket', if you will, into which the humerus fits, but I don't know enough about that to talk any shit, really.
I would take his advice and stop pressing, otherwise, you could have a full-thickness supraspinatus tear to show for it, like me, and that won't heal itself.