"Worried Man Blues"  is a folk song in the roots music repertoire.  It is cataloged as Roud Folk Song Index No. 4753.  Like many folk songs passed by oral tradition, the lyrics vary from version to version, but generally all contain the chorus "It takes a worried man to sing a worried song / It takes a worried man to sing a worried song / I'm worried now, but I won't be worried long."  The verses tell the story of a man imprisoned for unknown reasons – "I went across the river, and I lay down to sleep / When I woke up, had shackles on my feet", who pines for his lost love, who is "on the train and gone."  The Carter Family recorded this song for the Victor Talking Machine Company in 1930.  (More from Wikipedia)