Jim,
Have the doctors ordered a CT Scan, MRI or PET scan? If not, why not? MM causes bone fractures and pain. You should also be getting appropriate pain medicine. Don’t take “No” for an answer. You know your pain better than they do. You deserve the right treatment. Are you seeing a MM Specialist? I wasn’t. I’m glad I switched.

Had the similar problem, especially in the lower back, actually my spine. Come to find out had L1 vertebra fracture (VCF),then L2, L3 and L4 and then 3 middle of back surgeon filled with cement. Middle back was very much better but not lower back. Doctor would not do anything to lower vertebrates. The healed themselves but it took 3 years. Can now put pressure on my lower spine. Myeloma #1 damage is the spine. Went to a spine surgeon. You really need to see a spine specialist. Think my problems are typical. Your problem could be different. Hearth goes out to you. Use a cane, it helps. I still use one too much.

I have back pain, too. Some days are worse than others. My primary care Dr gave me hydrocodone/Tylenol rx that helps and my oncologist gave me script for muscle relaxer. Sometimes I have to take both. Biofreeze can b relieving sometimes. Hope this helps.