maternity pregnancy pants

I got this maternity pants that was a size medium . I knew a size small would have been too tight..

So I put on the pants and it felt good but later that night ( last night ) I started having pain around my stomach and mid back , lower back , shoulder blade on both sides ... usually that happens if I were my bra or pants on for too long . My bra, pants weren't on for to long. I don't think sunflower seeds with just the seed and not the shell . Not a good idea to eat . cause after I ate the seeds and took off the pants I was hurting...