Is prison rape real or just a story told to new inmates? What are the chances of being raped in prison being a new inmate?

Rape in prison is real. New inmates are the most vulnerable. The security level of the prison has some bearing on whether rape is more likely. Rape can be forcible or done through manipulation.  If they show kindness or are trying to be helpful, it is only because they want something. And if there offering you protection you can guarantee that there going to seek sexual favors. When an inmate comes in for the first time and doesn't know anyone, the clicks and gangs watch him like wolves readying their attack. They see if he spends time alone, who he eats with, they are like predators living in the wild. Most of the prisoners who rape are spending from 10 to life and might be part of a gang - they do not see themselves as homosexual. They pick a loner smaller weaker individual and make that person into a homosexual. Once they have raped and turned an inmate into their sex slave, they will sell him to other inmates or gangs.