Lower Abdominal Pain in Early Pregnancy: 16 Weeks - Is it Normal?

Question
I am 16 weeks pregnant.  Today when I was getting up out of my office chair I experienced very sharp pains in my lower abdomen.  Right in the center.  The pain kind of radiated through my vagina is what it felt like.  I have had no bleeding of any kind.  The pain was sharp at first, but has now dulled, but is still kind of constant and just annoying.  Are these normal stretching and growing pains, or should I contact my doctor?

Answer
It could just be the fetus sitting on a nerve or when you bend a certain way it could be hitting a nerve.  It could also be like you said growing and stretchign apins  You should see a doctor about this however because you never know and it is better to be safe than sorry/