Brief Answer:
Please give additional information, visit ER/nearby hospital

Detailed Answer:
Hi.
Thanks for your query, albeit short and specific.
To recapitulate: Female/86 - pain under rib cage - fullness - bloating -

Please give some more details for me to assist you better:
Since when are the complaints present?
Any nausea, vomiting, loose stool or constipation?
Black stools?
Is the pain referred to back or shoulder?
Any other information, please?

As per the short history, if the pain is severe, I would advise you to visit ER for clinical evaluation, examination and investigations like:
X-ray of the abdomen in standing position,
ultrasonography to start with.
Tests of blood: CBC, liver function tests, amylase, lipase, any other tests as advised.
This will give an idea about the probable cause and lead to the plan of management and/or further investigations to pin-point the diagnosis and get treated accordingly.

I hope, this answer helps you. Please feel free to give the details requested for. Awaiting.

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Brief Answer:
Diverticulosis

Detailed Answer:
Thanks for your feedback.
Diverticulosis is a condition where there is outpouching of intestine, more so of the large bowel that is colon.
One may get inflamed and infected to cause pain, bloating and other symptoms and this condition is called Diverticulitis.
This may be the cause of your symptoms.

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