Why do worms exist on my stomach if we humans have a strong stomach fluid? what to do/drink to remove worms inside my stomach?

Worms are not very common in the stomach, but primarily in the intestines. Have you been diagnosed with intestinal worms or other parasites? If not, you need professional care; you can't assume that diagnosis without professional evaluation and testing. If you indeed have a worm problem nothing you drink or eat will make any difference. You would need specific medications. Good luck.

The Life Cycles of worms can be complex and interesting. In many cases Human infestation is just a step in their life cycle. Fortunately the treatments are fairly easy and one's PCP can handle most of them. If they get complicated; the Infectious Disease Consultants are there. Meanwhile observation of personal and environmental hygiene help.