Have 640 ana, 74 iga tests, severe stomach pain, swollen red feet/legs, photosensitivity, fatigue, dizziness when walking. autoimmune disorder?

Maybe: Some of your symptoms and tests could be related to an autoimmune disease. You will need a more thorough history and physical examination to know for sure. I would recommend you see a rheumatologist to determine your diagnosis.

May be: You don't provide enough data for making a diagnosis. Your symptoms may or may not be connected. At your age, you may have a positive ANA with no disease associated with it. Iga of 74mg/dl is normal. See a good internist, and if necessary, a rheumatologist as well. Photosensitivity has also causes other than sle, including side effects of several medications.