I have pain in the middle of my stomach right under my ribs. It feels like expanding air. This is the 2nd time this week I've got this pain. Wat is it?

?Gallbladder Attack? The location and description of your pain may be secondary to gallbladder disease. These attacks typically occur after eating (esp. Fatty foods), last for an hour or more, are assc. W/nausea +/- vomiting, and may radiate into the back. Diagnosis is usually established with a simple ultrasound. I recommend that you see your primary care doctor for formal evaluation.
Hernia?? Without proper exam, it would be rather guessing here -- but if it originates in the bowel system, you may have what's called a hiatal hernia and you should see a GI specialist and get a proper evaluation and treatment -.