welcome to HCM,
thanks for consulting,
sir since you are travelling and facing a change in your food and drinking water, heartburn
can be the problem due to the same reason.
sir i would suggest you syrup sucralphate and tablet pantaprazole or rabeprazole
before food to decrease the symptom of your heartburn.
plenty of drinking water, a fiber rich diet, and some laxative for the constipation,.
remember the symptom of heartburn may persist if constipation is not relieved.
take care of yourself and get well soon..