Help!!! Severe back pain - Cervical Cancer

Hi all, my 1st time checking out & using a forum... I start radiation therapy on Monday. I need any advice for the back pain, I can't stand it anymore. It affects everything & I'm so very tired. I try to forget or just be ok with everything for a moment but the constant pain just keeps bringing me back. I use a mix of Co-codamol & paracetamol or Ibuprofen & paracetamol depending on how bad it is but they barely help to be honest. I've tried deep heat, tiger balm etc & they feel great for all of 2 minutes & I run out in the space of 2 days (besides my skin won't cope once I'm receiving treatment). 

Any suggestions? Hope your all doing as okay as can be given the circumstances x