Sorry to hear about the MRI results. My mom had herniated discs and I know that she had to go on oxycodone for it because it was so painful (I had never seen her cry before), so I can only imagine what you're going through.
Can the drs do anything about the disc disease? My mom went to a chiropractor and felt much better after messed up discs in her back, but it's not quite the same thing as you, so I don't know. She also got a steroid injection to help ease the pain.
I hope you feel better soon! I get agitated from bentyl too.