Drank some 7up on empty stomach, felt like pins and needles in stomach, very painful, right after I swallowed it. Lasted about a minute. What was this?

Gastritis. You may have some irritation of the stomach lining called gastritis. In patients who have this carbonation can be very irritating. I suggest that you avoid carbonation and also all anti-inflammatory medicines like ibuprofen and allow your stomach to heal up. If it persists see a doctor.