It's called degenerative disc disease for a reason. It doesn't get better and generally gets worse as we age. I suggest you check out the back problems and even the spinal cord disorders sections.
Your doctor is against giving more pain meds because the government is really cracking down on that. Sadly there's a negative stigma that all who use pain meds are addicts because a few use them illegally.

You may need to get referred to pain management to get further help with treating your pain.