Interesting question

I was asked an interesting question last night, time to address it I guess.

hell is it real or just pr from the church to keep you in line?

rather deep, sure, but one that is easy to answer, and, impossible to answer at the same time. The quick answer is yes, hell is a warning by religious leaders, there most likely is not a physical place called hell out behind Jupiter or in the center of the earth. Religions, all of them, tend to promise a reward for being good and a punishment for being bad, much like life.
If we breathe (good) we live. If we forget to breathe (bad) we die. Same goes for eating and sleeping. Then, as we become more cerebral, there are other innate goods and bads, or right/wrong. These are inbred, things like avoiding the rattle of a snake, not jumping off big buildings, not insulting an Eagles Linebacker in a bar.

Now, death sucks, it is the end, and so many people are afraid to die that others realized it would be a good idea to simply teach that death was not a bad thing, in one way or another we simply changed planes of existence. This has been taught in many ways, reincarnation, joining the Gods, Heaven and others. Ascribing this life after death to everyone didn't keep people from doing bad stuff until it was decided that humans could be even more controlled if living actions determined the after-life qualities. Hence, hell, or coming back as a bug, or instead of being a God, being a tree. So that is the simple version, the easy way out.
Now, for me, personally, not as easy to vocalize. Hell is not something that happens after death, it is right here, right now, as is Heaven. These words, as shown above, cover all the aspects of each religion, don't pigeon hole me into just one. If life is lived in a manner that would please your fellow man, chances are it would also please God, hence, Heaven. If life is lived in a manner that truly hurts others, then, well, internal hell. Everyone I have ever met that lived honestly in a manner that was proscribed by a deity was a happy person, those who pretended to live that life were miserable, and those that chose to live in opposition to were rudderless. Rudderless is neither sad nor happy, but existing, breathing, and living day to day in a manner that denotes survival, but not fulfillment.
I am not preaching any one goal, just pointing out that those who pick one, stick to it, and live it, are pretty happy people (the honest ones.)
For instance, a christian that judges others based on a choice of worship is not an honest christian, that person has missed the teachings of the Old testament. That person will not be happy.
Or, someone who is reincarnated in a higher caste must have been good in a previous life or if that person is not good in this life, the caste level will drop. All of this must be done honestly.
I mentioned honesty quite a bit, and am off the Hell topic pretty far, but they go together. Try it, think back to the last lie you told...how did you feel? Honestly, how did you feel? Were you proud of yourself for lying?
Thought not. Now, think back to the last time you felt pride for someone other than yourself, how did you feel?
Welcome to heaven.
Oh, and the worst lies to tell are those we tell ourselves.