So, my 30 year old son and I were out, at a buffet. He was standing at the buffet, and he explains something popped in his back. It took his breath away, and he was having a hard time standing up. It is about an hour later now, and the pain is still there, not as intense and no effect on breathing. The pain is actually to the far right side of his back...closer to his side (lower back). Any ideas on what would cause that kind of pain...with sudden onset, when he was not doing anything that would strain a muscle?