Hmm....I know 'Yawning' is normal for a betta, and sometimes if food is too large they'll cough it up several times before finally eating it.....but noises and coughing is a new one. What kind of noises? Could you describe them? Did he cough up anything?
I believe bettas are lower teleosts (boney fish) which would mean they are also what are known as physotomes...basically this means they burp to maintain the gas levels in their swimbladders. Perhaps that is what you are witnessing?