Could be reflux. You might be having a problem with reflux (gerd). Try cutting back caffeine (coffee, tea, soda), avoiding lying down for 1-2 hrs after eating, limiting mints, mint gum, citrus items. Monitor your diet to see if you can see a connection between food(s) you're eating and your symptoms and then limit those items. If these things aren't helping, see your doctor.
Helicobacter pylori. H. Pylori infection occurs when a type of bacteria called helicobacter pylori infects your stomach. When signs or symptoms do occur with h. Pylori infection, they may include: an ache or burning pain in your stomach, nausea, vomiting, frequent burping, bloating and weight loss. It is usually treated with 2 types of antibiotics given at once as well as an acid suppression drug. See your doctor asap.