Yet in the allegory written by C.S. Lewis under the title The Great Divorce, Heaven is actually painful, at least for those visitors from Hell who've been allowed to be there on a trial basis. The grass is like nails, the light too bright, the sounds too loud, and a small apple seems like a solid lead weight. Yet for the permanent residents of Heaven, it is indeed delightful.
What was Lewis implying by this detail in his parable? Why would heaven be painful?
Part of the answer may be in remembering that his writing is indeed fantasy. He's probably not making a literal assertion about experiences a human might have in the next life. Rather, he's embodied a spiritual thought in a concrete narrative.
Are there aspects of living as a follower of Jesus - aspect of life in the Body of Christ - which cause joy to those who've given up trying to justify themselves, but which cause discomfort to those who cling to the notion that their works will redeem their lives?
Imagine inviting a person to join an organization which allows him to set aside his own goals and desires, to set the needs of others ahead of his own, and to thoroughly internalize the view that his existence is characterized as service to his fellow human - that being a servant is the core of who and what he is.
Further, imagine that this organization to which you inviting a person will also require him to state - publicly, repeatedly, and frequently - that his innate character is permanently flawed, corrupted, and sinful; that he can never do anything which will atone for, or make up for, his sinful nature and the sins which he has actually committed; and that the best he can do is thankfully receive forgiveness which he has in no way earned or deserved.
Some people will respond to such an invitation eagerly - for some, such a place would be a joy. Yet others will quickly and decisively decline the invitation, seeing such a place as extremely uncomfortable. So, in this life, having a chance to participate in a lifestyle which offers a foretaste of heaven is in fact painful to those who expend energy denying the truth about their sinful natures and their inability to help themselves.
