I In 2012 Had Trouble With Chronic Pancreatitis With Each

I in 2012 had trouble with chronic pancreatitis with each attach worse and being hospitalized this went on for a year and then my gastrologist referred me to Indiana University. Dr Watkins preformed a sphincterotomy in 2013 and since then I have had no attacks. In August and Sept 2016 I had another attack and I am wondering why after all this when everything has been fine I out of the blue I would have another attack? Input would be greatly appreciated.