(Slipped disc has been a problem for me since before pregnancy so don't go panicking thinking you'll slip discs because of pregnancy!₩
I've had the same problem since my second tri started, but I have a slipped disc in my back. Ask your doctor, if it's a problem, s/he will tell ya!
I also stand for long periods of time (at work). Im now 18.3weeks. That sharp pain started for me at 12 or 13 weeks. I was told it's sciatica. Check with your doctor to be sure