pelvic pain anyone??

Anne
Is anyone else getting pelvic/lower abdominal pain? It feels kind of like muscles stretching that don't want to stretch. Not constant, but intermittent. Kind of stabby if I move too fast. I'm only 4wks 5 days, so I feel like that's early for round ligament pain to start, right?
This is my first pregnancy so I don't really know what to expect. 
Have you experienced pain like this? It's worse in my right side and spreads from the groin all the way across the lower pelvic region, even sometimes the top of my thigh. Maybe a 3 or 4 on the pain scale at its worst. 
Should I call the doctor about this or is it probably just normal stretching?