Low back pain extends to right abdomen

For the last 4 months, I have had pain in my lower right back that wraps around to the front of my body in my lower right abdomen. I've asked a doctor and he said it was something called S & I joint pain. I'm not so sure. It is especially painful in the morning when I wake up, but I'm usually fine in the afternoon. Although, it does hurt before a bowel movement too. Now, I don't know if this matters or not, but I have also had some differences in my bowel movements, as in they have gotten smaller and they seem darker. I don't know if that is related. Other than that I'm feeling fine. I find myself trying to sleep on my left side and that helps sometimes, but if I roll onto my right side in the night I usually wake up in a lot of pain.... What can this be? I'm in the middle east and do not have access to a doctor regularly???