They're so lonely they could die
This lyric was originally written as, "They'll be so lonely they pray to die."
While recording "Heartbreak Hotel," one of the more dreary lines was changed from "they'll be so lonely they pray to die" to "they're so lonely they could die." The change made the recording more acceptable to standards-sensitive executives, who were concerned about the original's message about religion and ethics. Presley continued to sing the original line in some live performances.
This alteration was not the only change that Presley made to the demo that songwriter Mae Boren Axton brought him. Her co-writer, Tommy Durden, later said that Presley so radically altered the phrasing, tempo, and tone of the song that he didn't recognize it.
Nevertheless, the song proved a cash cow for Durden. "Heartbreak Hotel" was the top selling single of 1956, eventually selling more than four million copies. In 2006, the song was re-released and it again reached the top spot in the Billboard Hot 100.
It's at the end of Lonely Street
The Heartbreak Hotel
The line was taken from a suicide note printed in the newspaper.
The inspiration for the song came when Thomas Durden directed his songwriting partner Mae Boren Axton to an item in a Miami newspaper about a recent suicide. A man had leapt to his death from a hotel window leaving only a short note, "I walk a lonely street." The victim could not be identified.
It's a little surprising—and a little sobering—that such a pervasive and hip-swinging hit had its roots in tragedy.