Hi there ~
I understand your concerns. I think that if you have had a bariatric surgery
, and having shoulder tip pain it is due to a distended stomach/pouch that is giving your diaphragm a really bad time. I would think that you might even have ulcers. I also believe that your blood gases are normal. However a visit with an internist or a family practitioner will help clear your doubts.
I hope this helps. Take care and have a lovely day!