Maybe a visit to the gastroenterologist should take place to rule out any underlying conditions like h pylori, a hiatal hernia , gastritis or any other problems. There are also a range of ppi available other than omeprazole like lansoprazole , nexus etc you could consider taking those. Also it takes a couple of days or weeks for them to take effect and also for any side effects to pass if any. You must also take them at regular times before food in the morning otherwise they are less effective . The most important thing is to have your condition diagnosed by an expert ..