Thank you for the query.
As you have pyloroplasty surgery before, the problem is probably at your stomach. IBS
can be diagnosed after ruling out all other reasons of the symptoms. As such surgery were usually performed in peptic ulcer
treatment, this is probably still bothering you. Moreover in 80s the Helicobacter Pylori
test was not known, you may have this infection left alone. Without eradication this bacteria, peptic ulcers wont get healed.
So it is advisable for you to have upper GI endoscopy
performed with H.Pylori test. If positive, antibiotics should be prescribed. Proton Pump
Inhibitors intake is also advisable for you.
Hope this will help.