I've had upper left and right side abdominal pain, fatigue, nausea and vomiting for six months that doctors cannot figure out.

Many causes: Epigastric abdominal pain, with right and left upper quadrant abdominal pain can be produced from many causes, including: gastroparesis, biliary colic, peptic ulcer disease, hiatal hernia, gastritis, diaphragmatic spasm, achalasia, duodenitis, reflux esophagitis, diffuse esophageal spasm. Etiologies and treatments for these conditions are not the same. More information is needed at this time.

Be persistent: If you haven't already, then see a GI dr. for val. at 6 months now, you issues are certainly chronic. You may need a CT scan, and a scoping procedure too-EGD. Blood work to check for liver or pancreatic, or underlying infections, etc. Sometimes, gall bladder issues may be caused by "sludge" which may not show up on an Ultra sound or imaging studies, etc. Best wishes.