What Causes Pain In Abdomen Post Placement Of ERCP Stent In Bile Duct?

I have to date in the past 18 months had 4 procedures ercps 2 under sedation and the latter under general anaesthetic. The stones were several large angular in my bile duct. The pain prior to my procedures was horrendous. My gall bladder was removed 18 years ago. I had an MRI scan last Saturday the 21st march.. no results yet. Today I had vague pains in the same area again which frightened me. I took an indigestion tablet called Omeprazole. I am 71 years old . The stent is still in situ! regards