I’ve written previously about the nature of Heaven and Hell. You can find it here: Vincent Guidry's post in Spiritual Musings
Short answer is, we choose to go to Hell, God doesn’t make us. What makes Hell necessary is exactly what makes Heaven so awesome.
Have you ever had an experience that was so perfect, that you didn’t possibly think it could be real? You’re looking around for the catch, almost relieved when you find out that no, this too eventually passed.
Heaven is that pumped up to 11. It’s not just your mind that rejects it, it’s your very sense of being that gets assaulted by such proximity to God.
You fall to your knees at the splendor. You can’t help but be convinced that you’re not worthy. You turn your face away from God.
And fall into Hell. You seek purification and salvation so that you can stand to be in that hallowed place again. God made Hell, not for himself, but for you.
In Hell your sense of self is assaulted, but not your sense of being. In Heaven everything looks the same, perfect angels singing perfect choirs everywhere you look. You can’t appreciate the differences between everything, because you’re so self-focused.
Hell obliterates that sense of self. You punish yourself, over and over again, until your spirit is purified. Then you can go up to Heaven and stand to be there with all of the amazement and splendor. Then you can appreciate the depth of tone of the singing, the fineness of the musical instruments, the keenness of the conductor’s direction.
Hell is nothing to be afraid of.