Do you mean Ruffin? If Padre Pio did tell someone else, fine, the story has legs.
I have read a lot on Padre Pio.
My objection was to this particular story, claiming that JPII was the source for an otherwise unreported story. I agree with Aremis Webb that JPII is not likely to have revealed something told him in confidence.
If someone else claims to have heard this from Padre Pio, then one needs to check that person’s credibility. The fact that there’s a remote source in Bernard of Clairvaux triggers skepticism in a hagiologist.
Michael Freze has an extended interview with Fr. Joseph Martin, OFMCapuchin, one of Padre Pio’s confreres from 1988. Martin explicitly says that Padre Pio never commented on which wound hurt the most. (Freze, They Bore the Wounds of Christ).
My copy of Ruffin is at the office. What does he say about the shoulder wound?
I have seen accounts that attribute it not to carrying the cross but to the scourging. A google search suggests that nearly all hits are variants on this recent Rega story which includes the Bernard of Clairvaux aspect.
Look at the pictures if you have the Ruffin book. It shows the shoulder wound on one of the pictures of the undershirt.