Question about occasional night time pain on right side?

Hi, all, my name is Kellie, I had Open RNY on May 10, 2003 and have lost and kept off 165 lbs. In the past few months, I have started having strange night-time pain that is driving me crazy. It does not happen every night, and has happened only three times during the day lately. It may happen every night for several days, then not happen again for a week. I don't see any type of pattern...food I eat, sleeping position, etc. It wakes me up in the night, first VERY nauseous and then the pain starts, always in the same place: right side, right under my ribs, deep inside, and extremely painful, like a knife in my side. The pain lasts 7-15 minutes, then just goes away, and the nausea goes away, too. After that, I am always sore and tender in that area for about 12-24 hrs. I have been seeing my regular MD, but I feel that he is guessing; we have tried several anti-inflammatories and nothing has worked yet. Any ideas?? I am waiting on a callback from my surgeon but thought I would check here, too. Oh, by the way, had my gall bladder removed 2 1/2 yrs ago. Thanks!