Professional societies have published several international recommendations on the need for gastroscopy. These are based on good research, and are updated periodically. In general, bloating and excessive belching alone is not a reason for gastroscopy, neither is acid reflux unless treatment has failed.
Bloating, excessive belching and acid reflux are common symptoms. Gastroscopy is a procedure that is done to establish a diagnosis, and does not treat these symptoms. Bloating and excessive belching is most often due to food intolerance.
The most appropriate test is hydrogen/ methane breath testing to look for sugar intolerance or bacterial overgrowth, while seeing a dietitian for a low FODMAP diet is also useful. For acid reflux, a course of anti acid medication (proton pump inhibitor) is appropriate. Gastroscopy is recommended only after the patient has failed a course of medication. In some cases, a 24 hour acid study may even be necessary to help with management
Nonetheless, I would suggest that you discuss your symptoms with your family physician. He will help to look for other symptoms that may be alarming, and that may require a gastroscopy to be done.
Sincerely,