Abdominal and hip pain, nothing found on scans

So I'm in a medical dilemma. I have pain in my right side abdomen and hip that gets worse with activity and sitting down/leaning foreword. Laying down seems to be the only thing for it. When not in pain, there's a tenderness and numbness in my right side hip/abdomen area, and it comes with random bouts of diarrhea and sometimes constipation. Several scans have found nothing, I've had a few CT scans of my abdomen, hip and pelvic X-rays, an MRI of my lower back, and no doctors can find anything. Has anyone else had a similar experience and can point me in a different direction? I've talked to a GI, general surgeons, a couple neurologists, an orthopedic, and been to the ER twice over the issue only to have them say they can't find anything.