was pac making excuses about his busted shoulder?

That shoulder excuse might be legit. I can tell you that shoulder was not 100%. But there are far more great boxers to have fought and end fights and they had none to say but the greatness of their opponents. Here they are;

1. Ali the GOAT fought Norton until the final round but never excused himself out of it when Kenny broke his jaw in the first few rounds of their first fight.

2. Harry Greb fought literally blind in one of his fights as in blind, but never excused himself out of it.

3. Joe Frazier was half blind and had busted rotator cuff (the first meeting) when he fought Muhammad Ali. He KD Ali and went to give the GOAT his first legit lose.

4. James Figg had that very high fever when he lost his first. The bout that he solely lost.

5.Nel Tarleton had only one lung when he fought his title fights. He didnt make ecuse out of it.

You see my friend there's simply no excuse.

Yes. The injury might be legit, but since he went on to fight instead of asking for postponement, he shouldn't be using it as an excuse.