Heck was born in Flensburg, Germany and grew up in Hamburg. In April 1943, when he was five years old, he developed a stutter after being trapped under a staircase after a nighttime British bombing raid during World War II. The stutter went away after he received training in classical singing at age 16. After completing "Mittelschule" (middle school) and a technical "Oberschule" (high school) he was trained as a "Technischer Kaufmann" (technical salesman) by Borgward in Hamburg and worked afterwards as a salesman. He left the company after four years.