Much ado about nothing
A great deal of fuss over nothing of importance.
The phrase 'much ado about nothing' is of course from Shakespeare's play - Much Ado About Nothing, 1599. He had used the word ado, which means business or activity, in an earlier play - Romeo and Juliet, 1592:
"Weele keepe no great adoe, a Friend or two."
See other phrases and sayings from Shakespeare.