Dear sir

Paiin related to unstable angina usually presents as referred pain which patient willl have arm pain and shoulder pain which is typically non specfic.

When it happen in younger age group symptoms will be more pronounced and less in older population

Normally ecg will not show up any thing but when you evaluate for exercise induced ischemia it will show up abnormalities

So recommended to undergo treadmill testing

Thanks

Hi, Welcome to Health care magic forum.
The pain in the chest and back, and reddish stools appears to be due to the gastric and intestinal pain due to the infection in the intestines.
I advise you to consult a physician for diagnosis and treatment.You may need to have gastroscopy, done for confirmation. The arm pit pain also may be due to the same pain referred to arm pit.
Avoid taking spices, junk foods, and oily foods.
Take more of green leafy vegetables, pulses, sprouts, and protein rich foods, to help recovery of the gut.
Wishing for a quick and complete recovery. Thank you.