uh can someone tell me what this pain could be?

I have been having right side abdominal pain for over a year now, and it has progressively gotten worse. When it gets really bad, i also spike a fever. Recently, it has also been having spasms where it "rumbles & vibrates", it almost feels like something is about to explode. the pain is severe, and it is like tearing and throbbing, it’s very hard to explain the sensation. any advice would be greatly appreciated. i have been to many different doctors, and they can find nothing. i also have a history of gastric ulcers and severe food allergies…i don’t know if that has anything to do with this.my bowels are normal. and i eat very healthy (i’m under a dietician). it’s really acting up right now and it also hurts to walk and move or do anything, i have a fever of 101.5. help please. like i said, i have been to many doctors, and have many tests done (most of which were performed a year ago) and everything has come back seemingly normal, but now it’s so much worse. like i feel like im going to throw up i just feel horrible. help! i have been avoiding all of the foods that i am allergic to so i don’t think that that has anything to do with my side pain. i have also get hives/rash when it hurts really bad. they are just red spots that aren’t really raised. i also have poor circulation, and my legs are almost purple, but i’m not overweight at all!
i am a 16 year old female, and i have had sonograms, x-rays, blood work, ct scan. most of which were over a year ago, and it’s getting progressively worse. oh and i’ve also had 2 endoscopys for my gastric ulcers that were caused by food allergies, but since i have kept the offending foods out of my diet, the ulcers have gone away. so, i don’t think that this contributes to my side pain. i really would like to get to the bottom of this, i have some more doctors appointments, but they are giving up as well. i can barely sleep the pain is so bad. i can barely walk, and when i do i walk with a limp cuz i can’t put full pressure on my right leg (same side as the abdominal pain). the pain is like parallel to my belly button under my last rib, but if it was appendecitis, wouldn’t they have found something by now?