Severe postprandial abdominal pain, all tests clear. Need direction!

Hello, I am 44 y. Im looking for advice on undiagnosed chronic abdominal pain. For months, I’ve had severe, blunt "hitting" pains and cramps. Sometimes it happens 5 minutes after eating – I end up shaking and crying in pain with intense nausea.

Tests already done: Blood work, Ultrasound, CT scan, Gastroscopy, Colonoscopy, Immuno-allergology. All results are normal (Negative for Celiac, only milk intolerance confirmed). Vitamins trigger severe pain. Antispasmodics (Algifen) provide only temporary relief.

Since standard mechanics are "clear," I suspect a functional or vascular issue. Has anyone dealt with something similar? Could this be a vascular compression (MALS/Nutcracker) or a motility issue? Any recommendation for specialists in Europe or the US for a second opinion? Thank you!