stomach pains

what could  cause stomack pains after 6 months of with no problems all of a sudden

i am 3 months post op and sometimes i have the same thing.  I find sometimes i forget to chew til applesauce consistancy.  Could that be the problem???

 Maybe gas?? I got a horrid attack yesterday. It started in my stomach (I think) and then I was cramped all over my tummy. Horrible. Still do not know what did it. Eating very cautiously today.