This is totally me too. I started getting them when we rented a house with stone bench tops. Couldn't work out why all of a sudden I was getting them. I started to think my shirts we catching on the zip of my jeans (they were a bit stretched!). Nearly all my tops had them. Then we moved to a place that had normal bench tops & it stopped. Now I'm back to stone bench tops & I'm getting them again. I finally worked out it's the button. The stone bench top is just at the perfect height for rubbing. It annoys me so much.