I don't have the same condition as you but I had my rectum and anus removed and at the same time a hysterectomy. The reason for this was that I had a secondary carcinoma growing alongside the rectum. The primary was in the bartholin gland in the vulva which was removed 3years ago. The latest op to remove rectum was last November so I am now with a colostomy.
I healed up really very well with no problems and things haven't been too bad at all, except since my op I have had a pain just below my chest just under my ribs, it was really bad after the op, and caused terrible pain on breathing, it has gotten a little better over time but still hurts a lot if I breath in deeply or yawn.
I keep telling my doctors who tell me it's because they did a lot of damage during the op and it's part of the healing process. Personally I'm not sure because it's been 5months since my op and its not getting any better and the constant dull sometimes nauseas pain is getting me down.
Anybody got any ideas what it is.