I would bet that all of the things you mentioned have combined to the "violent shock" factor.

Once last year I was heading out of town and had ordered new strings and cables for my solo cam. They were to arrive when I was out of town so I asked the shop to install them for me. When I returned and shot the bow I couldn't believe the noise and vibration I was experiencing. Turns out the cable was the wrong length so the shop had twisted up the cables to get the peak draw weight and in the process had preloaded the limbs. They then had to twist up the string to get the right drawlength. I was eventually able to fix it myself and have since found another shop or do my own work but my point is that this could be a large part of your problem. Check the cam synchronization (if a two cam) or cam timing (if a solo cam).

Good Luck!