I recently traveled to usa for a month and came back two days ago, and i'm really jetlagged but my stomach hurts/aches and i burp and fart frequently ?

Will take time: Sounds like you stomach did not like what you had to eat, and you are tired. These symptoms should subside in the next couple of days. I would recommend you get a couple of good nights of sleep in your bed. Regarding the excessive gas, if you want you could take Simethicone which is the active ingredient in Gas X. You can find this over the counter. AlkaSeltzer will also help with the gas.