Steady lower back pain

Rana • Married a year and a half, pregnant with first child.
Two nights ago I was in bed and started having strong lower back pain that lasted about thirty min and then went away , same thing last night. Now
It's back again, it's a steady pain, like  strong lower back cramps. Not stabbing pain. It's been like this for an hour. I never have back pain otherwise. I'm also having more frequent Braxton hicks. Could this be the start of something or is my body just prepping for the real deal.