Not sure what I'm feeling?

I'm only 16 weeks, I've felt sore off and on since becoming pregnant and doctor says its normal but I think I had my first Braxton hicks contraction early this morning, my stomach started cramping and got hard for a minute or two and then stopped but I still felt very sore feeling in my stomach off and on the rest of the day, listened to the heartbeat so I know the baby is ok but is it normal to feel this kind of soreness/ crampy? It's almost like a dull muscle spasm.