There's always a chance that it could be from that. But here's something similar from my experience.
My dad passed a couple years back from Lymphoma after fighting it off and on for over 10 years. In the few weeks before he died, he'd be getting minor pains in his hands from time to time. After bringing him back from a visit to the hospital one time, he insisted he was feeling so good that he wanted to do chores around the house (I convinced him otherwise). The next afternoon, the pain came back (throughout his body as well as his hands) and he passed in the hospital the day after.
The doctors never really did have a thorough explanation for the pains he was getting, but we were told that that type of pain is not uncommon to see once the cancer begins being quickly released from where it was primarily built up. Even though it was after ten years, he seemed to go so fast.
Point of what I'm trying to say is that these pains do happen before someone dies of cancer, and it may not necessarily be due to the mistakes with the pick. I suggest you talk to a doctor (maybe from a different hospital) to get a decent medical opinion on the matter if you are still concerned.
Sorry to hear about your loss.
