Hip/Abdominal Pain

So this Crossfit thing is crazy awesome but I'm having some muscle pain on my right hip/ab area. I'm assuming it's from having an incredibly weak abdominal wall/core muscles. Any ideas for how to fix it? I couldn't even do lateral leg lifts today like physically couldn't lift my legs because it hurt in that one spot and I was afraid to really do damage to it. Am I just being a baby and need to work through it? Has anyone else experienced this?