It's never stupid to see a doctor if you're concerned. You shouldn't be in so much pain that you're in tears. It could be something serious that needs to be looked at. See your doctor about this. It might be nothing, but it's better to know than sit and wonder if it is or not.
I would think if the back pain is severe and cramps strong that you should see your doctor or at least call your ob or midwife. It may be nothing but it may be something. Even if its nothing they might be able to point you to a physio therapist who can help your back. All the best for a smooth pregnancy!!
You absolutely MUST call your dr! You might be going into preterm labor.
Never be afraid to call your dr. There is no such thing as asking a stupid question. That is what they are trained to do and why you are paying them. It is far worse to not call and find out that by calling you could have a serious complication (even if the back pain is not a pregnancy complication, this type of pain and actually cause preterm labor).