Are chronic back problems related to drug addiction?

Sometimes. When pain is chronic you are likely to be prescribed opioid pain medication ( eg. Hydrocodone). There is a risk that such medication will be less effective after a while and the dose will be increased.Tolerance sets in and you can become physiologically dependent and or addicted. Prescription medication abuse is now the fastest growing addiction.
Might be. It could be since the pancreas can be indirectly affected by all the medications and can cause pain in the mid back so make sure you do not have pancreatic inflammation.