Well, there's no telling if it was from the ERJ or something else. But 10 years of throwing bags on the ramp didn't hurt it. And 7 years flying other aircraft didn't hurt it. But after 6 months in the saddle of an ERJ....
Like everything else in the world it probably was a little of this and a little of that. A genetic predisposition. Too much (or too little) calcium in my diet. A god forsakenly heavy flight bag, and too many trips up and down airstairs. And lifting onto the screening belt. And trying to place it in the overhead.
Maybe the ram's horns were just the last straw.