I have had these spasms, last about a minute. I had Whipple a year ago. I had them more at the beginning, very infrequently now. Mine cause pain across my back, similar to gall bladder or pancreatitis attack, and sometimes referred pain up to my shoulder. I notice if I eat at night, and lie down or lie back soon after, this can bring it on - have to get up and walk around. Someone suggested holding arms above the head, I do that too. It does go away in about a minute, but painful while it lasts. My doctors don't know the cause.