Hi welcome to Health care magic forum.
Thanks for choosing H.C.M.Forum.
You have pain in the upper left abdomen, radiating to shoulder blade. You feel a mass on your left upper abdomen.
It appears to be due to gastric irritation, or pancriatitis etc. the mass you are feeling may be external, and part of the skin like lipoma
, and no way concerned with the pain.
I advise you to consult a gastroenterologist
for diagnosis and treatment. You may need to get gastroscopy, and M.R.I.done besides other routine tests for confirmation.
Other possibility could be cervical spondylosis
, radiating to the stomach.
Wishing for a quick and complete recovery.