Several intestinal problems.

For as long as I can remember I've had to deal with what we thought was IBS, but lately I've been having severe side pains on my left side, under about the third or fourth rib from the bottom.  I'm beginning to find blood in my stool, and my intestine area now hurts after I poop.  Around the same time, I started to get horrible migraines, but I hadn't thought to put the two together until now.  If anyone has an idea to what we could look at, I would be very grateful.  I've had a CT scan several times, a biopsy of my stomach, an ultrasound, and stool samples so far.  Any suggestions would be most appreciated.