Welcome to the forums. I'm sorry it's pain that's brought you here, but hopefully you'll find some answers or get some ideas that might help.
Have your doctors considered that there might be some type of nerve damage going on? Have you had a brain MRI? You might ask your doctor to prescribe something for nerve pain, like Gabapentin (Lyrica - pre-gabalin). It's worth a shot, since you've pretty much exhausted anything wrong with specific body parts.
I hope you're able to find something that helps your pain. You might want to consider going to a Pain Centre to learn how to live with chronic pain - it does help when you have various tools at your disposal to distract yourself from pain, etc.
Keeping you in my thoughts and prayers,
DX: Fibromyalgia, Severe Myofascial Pain, Osteoarthritis in ALL my joints, Chronic Pelvic Pain, Surgical Adhesions, IBS, IC-PBS, Carpal Tunnel (both wrists), FAI, Type 2 Diabetes, Reynauds, Visual Migraines, Drug Related Hot Flashes, Hard Start for IV's, Unable to vomit due to surgery.
Meds: Oxycontin, Tramadol, Tramacet, Cymbalta, Cesamet, Flexeril