It could be either, but most likely BH. Just let your Dr know if you have any bleeding. Mine moved up by 28 weeks.
I had partial placenta previa, which is where the placenta covers the cervix. However once I reached 32 weeks it had moved. I think wwhat you're experiencing is braxton hicks contractions
What is plaventa previa? Also BH usually feels like a tightening in the stomach and pelvis area but are not supposed to feel like cramping. But everyone feels the differently