Norman, who held a six-stroke lead heading into the final round but crashed to a 78 in one of the greatest sporting 'chokes' of all time, said he was suffering from a bad back and it was not just a case of nerves getting the better of him.
"There's more to it than people realise because I did have back issues that morning," the 58-year-old told the "Australian Story" programme on state broadcaster ABC.
"I tried to walk it off but I couldn't. I told my coach, 'today's not going to be easy.'"
Norman ended up losing one of golf's most coveted titles by five strokes, his third agonising near-miss at Augusta.
The two-time British Open champion also finished runner-up in 1986 when he bogeyed the last hole to miss out on a playoff with a 46-year-old Jack Nicklaus.
A year later he was beaten in a playoff by Larry Mize, who chipped in to win.
Some will question why Norman has waited so long to break his silence on the back problem, but most golf fans but will understand his reaction to the galling Masters failure.
"I disappeared down to the beach after the U.S. Masters and lay on the beach and cried, because I felt like I'd completely screwed up winning a tournament that I wanted to win," the man known as 'the Great White Shark' said.
"That would be about the only time that I would have brought the emotion of a golf tournament back home."
Adam Scott ended Australia's long wait for a Masters winner this year, and dedicated his maiden major trophy to Norman, his long-time mentor.
(Writing by Ian Ransom; Editing by Peter Rutherford)
