Really scared..

Hey guys, so Friday I'll be 16 weeks with my first. Last week I saw her through ultrasound and everything was fine and healthy. But about 3 days ago I started getting these pains in my stomach. It's never in the same place each time, but I get kinda crampy aches in small spots on my stomach or sometimes when I'm walking it'll kinda shoot up the sides of my belly. They aren't real painful but they do kinda hurt. My boyfriend & I are really concerned that this could be bad. I've had no abdominal cramping and absolutely no bleeding, so what could this mean?