Dr said i had slight gastric erosion after endoscopy. everything else was normal.. biopsied the area and it came back as normal. how can that be?

No test is perfect: Sometimes mucosal pits or dents can look like erosions, and on stomach biopsy prove normal. Sometimes, tiny gastric lesions are targeted for biopsy, but surrounding unaffected tissue is obtained instead. Your doctor may be suspicious of erosive disease & will be gratified if you respond to his empiric treatment of it. Certainly express your concerns to the treating physician if still symptomatic.

Life stress: Directly visualizing the lining of your stomach is valuable enough for your dr to tell you that you have signs of acid burning the lining of your stomach. The good news is that the microscope did not shows significant damage from acid erosion. This life we live is stressful enough. Listen to your dr, take acid-reducing pills, and manage a known problem before you really drill down to an open ulcer.