I have a hiatal hernia and catch myself rolling over on my stomach when i sleep. well laying on your stomach cause the hiatal hernia to get bigger?

Since the original surrounding anatomy of the diaphragmatic aperture around the esophagus can be slowly enlarged by increased intra-abdominal pressure from a prone position, it is likely that a symptomatic hiatal hernia will become larger, with more potential for adverse symptoms. A diet to reduce weight will be beneficial to reduce need for surgical intervention.