Brief Answer:
Possibly due to gastritis. Could also be due to gallbladder cause

Detailed Answer:
Thanks for asking on HealthcareMagic.

I have gone through your query very carefully. Your friend possibly has gastritis or gastroesophageal reflux. Ensure that she takes plenty of fluids and ORS (oral rehydration solution). Keep her warm. She has possibly done the right thing by sitting in the hot tub. Her condition needs to be evaluated and it would be a good idea to visit the ER if the condition does not stabilize soon.

In order to be relieved your friend needs to do the following (long-term):
* Avoid spicy food. Take small but frequent meals. Avoid long gaps between meals.
* Avoid alcohol intake (if it a part of her habit).
* Take Prilosec (omeprazole) once daily before breakfast.
* Take plenty of green leafy vegetables as well as other sources of dietary fibers. Take fiber supplements like ispaghula/psyllium husk or senna. I would insist her to increase your dietary fiber intake.
* Regular morning walk and exercise to keep the bowel movements proper.
* Take curd or yogurt on daily basis. It contains beneficial bacteria and should help.
* Stress reduction has a very important role to play. Yoga and meditation should help.

Another possibility to consider is gallbladder problems. In such a case, a clinical examination would be needed first and would need to be confirmed ultrasonographically. Treatment plans can be made accordingly.

Clinical examination is also needed to rule out an infection and sepsis as a possible cause.

Hopefully, that should help.

Let me know if I could help further.

Regards

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