Everyone is different and feel them differently. I also find mine change the later part of pregnancy. Most of the time they start out as tightenings on the lower tummy uncomfortable but very manageable. And as I get closer to baby coming it becomes my whole tummy that tightens and sometimes they take my breath away other times I feel them painful.
When I get bh my lower stomach tightens and becomes super hard. It also takes my breath away a bit. Mines a little uncomfortable but doesn't hurt.
Im not sure either. The other day i had this god aweful pain in my belly and back amd left hip all at the same time. It stayed for anhpur on n off