Why is there blood in my stool?

Sometimes when I have a bowel movement, it is extremely hard to get out. Kind of like constipation but also when the stool passes it is hard. Then when I wipe there is bright red blood on the tissue. I was diagnosed with Crohn's disease 5 yrs ago and had emergency surgery to remove part of the bowel and small intestine but have not had a single flare up since the surgery. I have also had hemorrhoids a couple of times in the past so I'm not sure if that could be it.