I had IBS that was painful like that. Stay away from milk, dairy products and anything with milk or dairy in it. If that works, it was IBS.
mrsboston3122 and Alistar. it could very well be the Gallbladder but i personally believe that it would still fall under intolorence. why remove something if it can be fixed. if it cant, well that is a different story but i would dig a little deeper into the intolorence thing because the doctor sure wont.
I agree with Amuro1013, that it may in fact be your Gallbladder. I had similar pain as you after losing 30 pounds. The pain was HORRIBLE and just kept getting worse. Does the pain sometimes come a couple of hours after you eat or early in the morning, like wake you up at like 4am? Mine started at my lower right side and was a couple times a month, the a couple times a week until it was everyday. It just kept getting worse and then moved up to my upper right hand side to the center of my chest and through to my back. I went to the ER and they gave me an ultrasound and sure enough it was my gallbladder, I seen a surgeon and had it out 2 weeks later. Not before I went through testing for everything else/ it was a long process. I even had a heart cath at the age of 28 because they thought it was my heart. I still get the pains but they are not as bad and only last for seconds, they say it happens sometimes when you have your gallbladder out but I do feel so much better, I can eat with no pain after:) Not saying that is what it is but is sounds like it to me. Maybe when you see your doctor you can ask them to check on it for you.Good luck.
Tanya
Have u noticed these "attacks" happening at a certain time of day or after eating certain foods? It may be your gallbladder
a food , spice or perservative intolorence could be your culprit. google thyramine intolorence. its a type of food sensitivity. this may lead you to the answers your looking for.good luck