I have no confidence due to this?

Hi,

Im a 25 year old male. I have a long history of stomach issues and that is not this question is all about. I'm having bad breath all the time and i have no confidence in talking to people. I chew gum all the time when im around people and this is totally embarrassing to even discuss it with a doctor (dont even know which doc to consult). Ive read, it could be related with the stomach issues as well, which is why i mentioned it first. I brush 4 times when im home, when i have work it would 3, im sure its not my hygiene (thats why im not considering a dentist).I have a strong feeling it could be something else. Is there anything i could do to get rid this and find out what's the real cause? Please help me out here.Thank you.