Having Digestive Problems, Fatigue, Sleeplessness, Pink Patches On Neck, Chest. Treatment?

I m a 16 year old female, I have been having digestive tract problems, including inability to eat a meal without feeling and or getting sick about an hour. Also, right flank and back pain , patchy skin that becomes red and pink on my chest as well as neck at various times that lasts about a day. I do not sleep well and am very fatigued. I am on no medications except for 1,000 mg of Biotin , a daily multi-vitamin and 500 mg of vitamin C . I have gone in for several tests, they have checked my gallbladder , kidneys, and liver . I cannot go on living like this, embarrassed to eat with my friends because I cannot keep the food down most times. I get asked when my skin flares the the patchiness described above what is wrong with my chest and or neck. Do have any test that I could bring up to my doctor or a way to treat whatever is going on?