Ab pain only at night

I am 34 yr old and I've had abdominal pain for the last 9 yrs. The pain only comes at night after lying down a few hours. The pain intensifies when I take a deep breath. The pain is relieved mainly by just sitting or standing up. I also urinate when I get up to relieve some pressure which helps a little. I Over these 9 years I've had 2 ultrasounds, 2 CT scans, 2 Upper GI endoscopy (EGD) with biopsy, a colonoscopy, barium x-rays, and the bravo ph test for acid reflux. Nothing abnormal was found except one EGD showed a small hiatal hernia. but the 2nd EGD didnt show hiatal hernia. My doctor said it could be a small and 'sliding' hiatal hernia since one testsaw it and the other didnt, but that hiatal hernias dont cause pain usually.
My GI doctor says he is done with me. I dont know what to do now. The pain is worsening. I have to sleep practically upright to not have this pain. I'm really worried about what the next 10years hold for me. Does anyone have a clue what this could be?