Is it normal for my stomach to be hard and sore during pregnancy?

Possible: Pregnancy puts a stress on your entire body including your stomach. Your stomach shifts throughout it and its motility (propelling function) changes. Although, description of it being "hard" and "sore" is very non-specific, i would assume a lot of if not all women can describe their stomachs at some point during their pregnancy the same way. If in doubt, i would consult with your obgyn.