Severe abdominal pain and nausea, er, labs ok, ct ok, no blockage, could it be a stomach ulcer?

Maybe: There are many causes for abdiminal pain. Peptic ulcers may cause upper pain which is aggravated by foods. Often antacids provide improvement. If your physician suspects an ulcer, a trial of medication is in order. Endoscopy is often performed to confirm the diagnosis.

Pains and nausea: There are lots of reasons for abdominal discomfort, and not all of them are due to the GI tract. Even "functional" syndromes may be present without underlying "disease." if pain with meals consider peptic (acid), biliary, or pancreatic disease. If bleeding or tenderness is present, this suggests inflammation, ischemia, or infection. Exquisite tenderness is quite concerning. Please see your doctor.