Hi There ^_^
I have also had my gallbladder removed, and sometimes get "phantom pains" in that area. Perhaps that is what's going on. I think, and I could be wrong (how embarrasing) the area right under the rib cage on the right, is home to the liver (Mr Gallbladder was evicted from that same area I see) however I am not aware of the liver actually producing pain...so so not a doctor, but then again the gallbladder sure did cause pain!
Sometimes its gas, but I'm sure you know that - I'd keep tabs on any other symptoms, make a journal of it and if you see a trend or anymore indications that may require attention, definitely see your doctor, let them know what the deal is - and if you havent had blood work done recently, have it done.
Good luck! ^_^
It could be your kidneys try drinking alot of cran berry juice im not a doctor but you never know hope this helps