Tightening in stomach?

It's not like my normal BH it's a constant tightening that seems to not be going away. My back has been a little achy also. Is this just the round ligament pain or should I be worried? My stool has been green the past few times i've been able to go . My mom said it sounds like I may have an infection but not sure if all of it is connected. TIA and sorry for the TMI!  

Stool changes color based on what yoy eat. Browns, greens, and yellows are normal. Grey or red streaks are cause for concern. As far as constant tightness though I'm not totally sure. I know for me if I eat a larger meal or drink a lot my stomach feels super tight for a while.