Apparently a huge percentage of people have it, especially in developing countries but not limited to them, and it is known to cause a lot of problems though there is debate about possible benefits of it.
https://en.wikipedia.org/wiki/Helicobacter_pylori
There is a sort of cure for it involving proton pump inhibitors and antibiotics. After which, your stomach feels a ton better and your probability of stomach cancer likely decreased.
I had chronic stomach aches since I returned from a long traveling in Thailand. Only recently did I apply this treatment. I've never had such great stomach health.
This was self-diagnosed and treated. I know what many on hacker news thinks about non-experts talking about these sorts of things in recent months. I think that's absurd.
Help yourself because no one else is more invested in your health.