My newborn DS has reflux, (4weeks old) after a feed, he always burps(can take a while) and does some possetting, some feeds more then others.

Sometimes i put him to bed as i think that he has got rid of all his wind etc, only to find out later that he has been sick in his bassinett. he always turns his head to be sick. i am worried that he can choke.
How can i prevent this, and does this happen to anyone elses bub?