crohns disease diet

i had surgery for chrons disease 7 years ago and have been symptom free since then, quite a few months ago i went on a diet to loose weight, cut out all unhealthy fatty foods but in the last couple of weeks i have been eating not so healthy and for the last week have had pain in the lower rite and left part of my stomache, crampy type pains i said to myself ok, this is probably just the change in diet, body not being used to all the rubbishy foods but then tonight i had that pain for a while, it came and went and came and went and then all of a sudden there was this pain under my ribcage sort of, goodness i thought i was having a heartattack. I am petrified of having another colonoscopy as the previous one i had wen i was diagnosed did not go well. can they simply to a blood test or do u have to go thru those awful other tests :S. it shot thru to my back and for an hour i could hardly move. . IF the chrohns returns, how does the dr find this out. . i guess what i am wondering is. . i took nerophen for that and it has worked but i am worried that this could be the start of the hole awful ordeal again.