Have you heard of Epipoic Appendagitis, I had symptoms of lower left pain it was really bad. After spending time in the hospital on IV antibiotics and the pain wasn't getting any better, to cut a long story short they took me to surgery and this is what they found Epipoic Appendagitis. It is where the intestine has these fatty pockets on the outside of it, and some of mind got twisted and this is why I was in so much pain. Normally these twisted pockets fall of on there own, but because I was in so much pain they did the surgery. Which I was told rarely gets done, the sugeon who done mine he said I was the first person he had preformed this surgery on in the 23 years as a surgeon. I thought I would share this with anyone suffering with left sided pain which will not go away, even after all the tests come back not showing this. Good luck, Liz.