I have been experiencing this as well this past week. I'm 25 weeks pregnant (6 months along). Sharp shooting pain in my lower back/upper butt.And I can't move my upper body or my legs without getting this shooting pain! It makes my days so difficult to take care of my 3.5 year old son.
People keep suggesting it's sciatic nerve problem, but I do NOT think so as the pain does NOT go down my leg, nor do I get any tingling/numbness in my lower legs or feet.
You are not alone, & I have been reading the answers that others have provided for you, to use for my own situation as well.
I have never miscarried, this is my 2nd pregnancy, but I think what you are describing is exactly the pain I have been feeling as well.
I noticed your post was from 3.5 years ago. Did you ever find out what the problem was??
Sincerely,
Lissa