I Seem To Have Chronic Constipation. My Doctor Prescribed Amitiza

I seem to have chronic constipation. My doctor prescribed Amitiza for me again last week and I am still having problems. It worked for me last time I was having this problem, but this time seems much worse. I feel bloated throughout my whole upper and lower abdomen and don't feel like I'm emptying out. I have bouts where I feel like I'm about to starve, but try to watch what I'm eating (the scales are not my friend right now). Yesterday evening I had pain up under my breasts across the top part of my abdomen, I get them sometimes it feels like a muscle knotting up and cramping, used to only be on left side, but now happens on both (I have hietal(sp?) hernia but it is in the center between breasts).