Your stomach tightens up and feels hard to the touch. It's difficult to describe exactly. It can be uncomfortable, but it shouldn't hurt.
This, exactly. I started getting them a lot more, obviously towards the end but I remember with DD, I got them at the end of my 2nd tri and all through my 3rd when I was walking. They continued after I was done too, along with leg cramps...yay. I remember sitting at my desk and getting them sometimes. They are WAY WAY less on the pain scale compared to contractions!