Rectocele usually shows up as a bulge on the back wall of the vagina which overlies the rectum. Rectoceles which are small and stay inside the vagina are usually not a problem unless they are symptomatic (i.e., they cause problems with emptying the bowels, or require you to put your fingers in the rectal area to have a bowel movement). Larger rectoceles usually are treated with surgery to make them smaller.
If you are aving symptoms, please see your surgeon and ask them to evaluate you for repair.
Don't know if you are still around, but I had a total abdominal hysterectomy in June '06, A & P repair in 10/06. I, too, have that feeling of there being a lump in my rectum. Gyne insists there's nothing there. I am having bowel problems since the A & P repair. Are you? Another person told me that her UroGyne said her pelvic floor muscle is so tight from the repair. I have no idea of what to do about it. Hopefully, the doctor will come along with some advice. If I find out anything more, I will post to you. I hope things improve for you.