Previously i omitted what may be an important clue. The problem began when starting engine in A.M., hearing lowed whirring meta noise. After driving & engine warmed the noise subsided.
Yesterday after the mechanic diagnosed the problem; no noise today?? A Rep at Pep Boys said it sounded like pump bushings, and suggested replacement.
Do you have just the correct amount of fluid, not too much or too little. Try some Lube-Gard power steering additive first.