Lower back pain

I keep getting sharp shooting pains throughout my lower back. It's not constant but it comes and goes. It's been going on like this for like an hour now. It doesn't feel like cramps, it hurts so much and it doesn't matter what way I lay down and I've been drinking water and it's not helping. I'm 17weeks and want to know if this is normal or should I be concerned? Please any advice would be appreciated, I'm getting worried.