I am going to guess referred pain from your sacroiliac joint (in your pelvis). Make sure you wear good supportive shoes (aka...try to avoid heels) and talk to your OB about safe back and leg stretches. Or a referral to a Physical Therapist wouldn't hurt either. Hope you feel better soon!
I had issues with sciatica, which is in the same vicinity. I found stretching really did help (ask ob/mw for possible ones to use). The other thing that I wish I had done earlier in my pregnancy was get a belly band to help relieve some of the pressure. But ditto JLPT... wear comfortable shoes and possibly get a referral to a PT.
I'm due with my second child in December and I have awful hip pains! One thing that helps me is to stack three pillows (yes three) between my knees when I sleep. If I feel pain during the day I try to do pilates stretches or a 20 minute Zumba work out. It is painful!
Re: Hip Pains
Jennie