What is normal pain after Colostomy reversal

I am writing this looking for anyone that can give me insight into life following a colostomy reversal.
My Mom had this surgery on Dec. 2nd 2008. Now almost 3 weeks later she has not had any relief in the pain area. There is no real defined times when the pain comes. It seems to be more often then not though, and I am worried it is affecting spirit greatly. Wonder if anyone can tell me if this is normal healing process or if she should be looking at something possibly being wrong. Her pain is in her lower back often and in her bottom end, seeming to be more specificly in her left butt check and shoots up inside. Her pain is the worst following a visit to the bathroom, but does occur with out warning during all times of the day. She realizes the unfortunate thing is all things take time and it really has not been long enough to obviously completely heal,but her days are still consisting of being housebound because she is so warn out from all the pain.
Anybody with any insight, suggestions, or welcoming advice would be greatly appreciated.
Thank you.