I agree with JoyRenee! I'm 29 weeks pregnant and last night my left hip hurt so much I could barely walk straight! It was around my hip and right by my lower back. So horrible! But I've come to terms that I'm pregnant and I'm going to hurt and be uncomfortable no matter what!
Sounds like sciatic pain to me! I wouldn't go to the ER and pay a huge bill only to be told, "You're pregnant and will have weird pains and there's nothing we can do for you. Go home and rest."
Your hips are expanding and tilting and your baby is most likely putting pressure on that sciatic nerve. It was so debilitating during my pregnancy with my second daughter that I could barely walk or move sometimes.
How far along are you? In any case, from what I understand, any "pain" and you should go to the ER, if it's bad or lasts a few hours. Let us know and good luck!
It might be round ligament pain or sciatic pain. If it goes on for too long or is unbearable or you just feel like something isnt quite right, let your doctor know. I hope you feel a little better soon.