Brief Answer:
Needs to rush to ER; take a PPI like Pantoprazole.

Detailed Answer:
Hi.
Thanks for your query.
Noted your history, albeit short and specific.
Whenever there is severe pain in upper abdomen accompanied by back pain we have to rule out serious diseases as a cause.
There is a possibility of pancreatitis or gastric ulcer on the posterior wall or pains by some conditions affecting the retro-peritoneal structures such as aorta or so. Occasionally Heart related condition may have similar symptoms. Ulcer perforations also needs to be ruled out.

Hence I would advise you to visit ER as soon as possible so that the clinical evaluation and supportive investigations like tests of blood for pancreatitis, upper GI Endoscopy, high resolution Ultrasonography and color doppler, X-ray of abdomen in standing and laying down position of the abdomen can be done to have a proper diagnosis so that a specific treatment can be started. Stabilization of general condition after clinical evaluation may also be needed.
It is good that you have taken Rolaids, also take a PPI like Pantoprazole or so if you have with you.

I hope this answer helps you in decision making and getting a proper diagnosis asap to get an appropriate management.
Late diagnosis can have more complications.
And if all the investigations come back normal we are happy to rule out serious conditions and have symptomatic treatment as some conditions need prescription based medications also.

Please give feedback.
Take care.
With Regards.

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