In "The Shawshank Redemption", Red finally gets parole. What are the problems he encounters in life on the outside?why does king choose to show...

Part of what King feels is the curse of institutional life is that it chains us to routine.  For example, Andy endures the first couple of years of prison life because of his routine, and living life in this manner, without hope, promise, or difference, allows him to withstand the difficulty of the institution.  For Red, his routine lies in knowing the institutional world in which he lives.  He knows the prison, knows what he can do, understands it well, and lives his life in accordance to it.  Prison is his routine, and it's something that he has known for almost four decades.  When he leaves prison life, his routine is gone.  His familiarity, his social acceptance, his realm of predictability and comfort disappears as he has to endure life in the world outside of jail.  The book details the problem he encounters:  The lack of respect, the flimsy notion of power, the disparaging comments and looks, as well as the complete openness after 40 years.  For four decades, Red has become accustomed to the confines of Shawshank and it is startling to suddenly  be thrown into a world of freedom and limitless boundaries.  Consider this similar to Plato's Allegory of the Cave, where the person has been chained into a cave for so long that they don't know what sunlight is.  When they actually see life outside the cave, it must have been overwhelming.  It is the same with Red and his life outside of Shawshank.   This feeling of being overwhelmed, almost crushed with the expansive nature of freedom and lightness (a true example of The Unbearable Lightness of Being) is difficult for Red to take.  Recall why he was not supportive of Andy when he spoke of his vision of freedom at Zihuatenejo.  Red feels that there is no role for him in such a setting because of its wide scope of freedom, and when he is released from prison, it is the same experience.  Institutionalization creates a pattern, a routine, that allows individuals to live and endure life in this sequenced and predictable existence.  To take this away after so long and then abandon them with only saying to them, "Go and live," is too much for Red when he is first released.