Flexible sigmoidoscopy

It sounds to me like you would benefit from asking more questions of your doctor.  If you have a large stool that is not moving, you may have diarrhea going around it.  But a sigmoidoscopy sounds like a very invasive procedure to remove a stool.  Unless you have other conditions like kidney failure that makes laxatives a problem, I would ask your doctor if laxatives, or enemas could alleviate your problem.

I would relax Tasneem. Yes flexible sigmoidscopy looks for this among other things, but you don't get sent for one with the doctors thinking "this must be cancer." I had one last week and both my GP and consultant thought there was nothing to worry about, but generally send you as a precaution.

You have to view this in context that sigmoidoscopy is a massive nationwide screening process and only a tiny proportion of these procedures will find anything to be a concern.

Its not the most pleasant procedure but not terrible either. And the enema they give you beforehand also gives you a darn good clearout which has now completely sorted out my own symptoms (rectal pressure).

I'm no doctor, but googling what you describe, the leading culprits which they will test for would seem to be H Pylori, IBS, digestive issues and diet.

Try to relax - I know its not easy but after two endoscopies and a sigmoidoscopy I find it stunning how symptoms can often clear up straight afterwards.