I didn't type "best bra for nurses." I'd done that search a hundred times. Bought those bras. They all did the same thing.
Instead I typed: "Why does underwire get worse with movement?"
And finally, after 19 years, I had my answer.
Underwire is rigid. Your body is not.When you bend, twist, reach, or walk, your body shifts. The wire doesn't move with it.
Every movement creates a tiny gap between where the wire is and where your body went. Then your body comes back. The wire is now pressing into fresh tissue.
It's not pressure. It's grinding.