I hope you have spoken with your Drs about all this. I never had constipation during the chemo and radiation, but the exact opposite. As for the pain on the table, is it from being on the hard table?
I went through 6 weeks of chemo and radiation, then off for 6 weeks, then had my surgery on May 8th. From the time I was in the hospital I started complaining that my bottom hurt and was sore. It continued and I've had to take pain meds just for that pain! At first, I thought it was being on the hard operating table for so long. Then, I thought it was because I had lost so much weight and had no more "padding" back there. I just don't know what it is really... I think it is finally getting better - after 2 months!
Please, speak to your Drs. and techs about this and see what they recommend. I wish you all the best!