I started getting these "catches" especially on the right side of my lower abdomen almost immediately into the pregnancy, but now that I'm in the second trimester and things are starting to REALLY stretch, I get them more often. Yeah, I'm talking about round ligament pain... I usually get it if I suddenly stretch up on tippy toes to get something, or make a sudden turn in bed. Usually it's just a sudden stretching catch, and then it's over.
Talk about growing pains.