My 4mo. was recently diagnosed with reflux. He did the same while feeding. Arching his back, grunting, etc. Symptoms he had were loud poops, dry cough, bobbing on and off while feeding, fussy feeds and after for 30-60 min., ate from bottle w/ little problem because it comes out faster and cools his throat. Because he wasn't eating much, he ate during the night. My milk supply went down some which worsened the problem. He's on Prevacid now. Somewhat better.