So, I suspect your evening indigestion is not a big deal, and is on account of gas
You can get gas
from many things, including the constipation and H. pylori we've been talking about, but it can also come from: Heavy meals, skipping lunch, rushing while eating, exercising after eating. When you feel those gas pains strike, you can try an alka seltzer. When I was young, I would eat a huge lunch after church on Sundays, and it always gave me terrible gas pains.