Ruby,
Normal humans move away from pain and discomfort. They also move toward something perceived as beneficial. This is called motivation direction. One repels, one pulls.
Imagining some sort of mass instantaneous masochist indulgence on the part of diverse, previously unconnected people is far more far-fetched than believing they were telling the truth about being eyewitnesses to the miracles and resurrection. Even his enemies conceded that his miracles were real. (hostile witnesses)
Convinced that they had found the solution for death, having witnessed the death and resurrection... they simply saw no downside in telling others about it, since death had no hold on them.