Thanks Steve. Assuming it was a bad rep that caused the injury, would you say that very carefully reintroducing the bench with light weights and progressively increasing weight is a good idea?
Also, I came across
this article by Eric Cressey, discussing AC impingement. Now, there were a few red flags that popped up (although I'd need to spend some time thinking about the mechanics to see whether his ideas hold water), but he did mention scapular instability as a potential culprit.
One thing I have struggled with in the bench is keeping my shoulder blades retracted. Perhaps failing to retract them contributed to my injury.