Back pain may be experienced during any point of your pregnancy; however, it most commonly occurs later in the pregnancy as the weight of the baby increases.
Occasional or sporadic abdominal discomfort during pregnancy similar to menstrual cramps may simply be a sign that your womb is preparing to carry your baby through the next nine months of pregnancy.
If you start to experience chills, fever, spotting or bleeding, see your gyn since this can be something more serious.
If you have a back pain that spreads to your abdomen on one side, you can be examined for kidney stones.

Best wishes!

I would call your gy because it could be a misscarrage starting to happen!! Rather be save than sorry!!!! I would just let them know what is going on with you.