Barium enema lead to colon obstruction

I was recently admitted to the hospital five days after having a barium enema during a routine colonoscopy in which the camera couldn't get far enough due to a redundant colon. Several days after the colonoscopy, I began having cramping and lower stomach pain. The hospital found that my large colon was completely blocked by a large slug of solidified barium. I was given enemas and later passed, (with much pain I might add), a solid cylindrical silver gray putty like slug of barium about the size of a Coke can. I am wondering how common something like this is because I am definitely scared to death of colonoscopies now. I am also wondering if there is any danger of more of this stuff being stuck to the walls of my large colon. I saw an X-ray of my large colon after I passed this barium and they were still glowing bright white.