I've wasted my breath.

Hi guys?

I'm a S. Korean eager to learn new English expressions.

The one I came across today is 'waste one's breath'.

Say, I went shopping today and it was of no use at all
as there was not the item I had intended to buy.

Here, would it sound okay if I said,
"Oh, I went shopping today and there was not the item I was looking for.
I just wasted my breath."?

How does it sound?

Is the expression 'waste one's breath' only applied to the cases
where you have an argument and it's meaningless to keep talking?

I'd appreciate your comment, guys.