To the Editor:

In your March 27 article on the duplication of Michelangelo's Sistine Chapel frescos on the ceiling of a church in Worthing, England, the artist Gary Bevans says he ''might have to lie on his back and paint as Michelangelo did all those years ago, sometimes only 18 inches away from the ceiling.''

Mr. Bevans has repeated one of the most widespread myths of the manner in which Michelangelo painted the ceiling in Rome. The master painted the ceiling not in a horizontal, but in a vertical position. This is attested to by visual and literary evidence. Next to one of his poems describing his condition while painting is a drawing showing the artist erect with right arm upward painting a head on the ceiling. The poem graphically describes his great physical discomfort, which Mr. Bevans echoes when he says:

'Physically I know what he went through. I always have a tremendous backache and neck ache.''

In the poem, Michelangelo says: My belly's pushed by force beneath my chin . . . My beard toward heaven, I feel the back of my Brain upon my neck . . . My brush, above my face continually Makes it a splendid floor by dripping down. My loins have penetrated to my paunch . . . In front of me my skin is being stretched While it folds up behind and forms a knot, And I am bending like a Syrian bow. SAUL LEVINE Westbury, L.I., April 2, 1989 The writer was formerly on Columbia University's art history faculty.