I think it's pretty obvious that Michaels was playing up his back injury and it wasn't in service of the match. Clearly a man who resents that he has been overtaken by Austin in the backstage and popular hierarchy, and is throwing a temper tantrum/manipulation fit before he unnecessarily sits out of wrestling for half a decade. Seriously go back and watch this. His selling is great but obviously contrived because he would not be taking those bumps if his pain was that bad that he had to react that way in between every move. He was making everything about himself and in the end it didn't matter.
Anyway this match is way better than I remember. I always found it a little underwhelming. But it's very fun. Not amazing, but fun and interesting to see Michaels' temper tantrum reaction to the changing of the guards in real time. He was a very talented performer. Imagine if he wasn't on drugs during his prime. I think he could have been a better opponent than Bret for Austin in some ways, as the two of them together were better equipped to have the fast paced, Steamboat/Flair style match that Austin was a proponent of, especially in his WCW time. I guess that's kind of crazy to say considering how good Austin's matches with Bret were, but I think we missed out on some good stuff with Michaels' early retirement.