This is called MOH (Medication Overuse Headache).... and people on chronic painkillers can develop it, regardless of what type of pain is being treated.

There is no treatment, except for reducing or getting off pain killers.

It is a neurological condition generated in the brain in response to opiate or other analgesic use.

Thought initially to be mostly found in chronic headache patients, also chronic pain patients who use opioids daily, may develop headache as a side effect of opioid therapy.

This is thought to arise in the glial cells of the brain...those cells which support other brain cells. But its exact mechanism is not understood as yet. Much of the research is in Europe and slowly spreading to the US.
I've had two long seminars in this topic, in the last 3 yrs.

You can Google MOH headache, for more details. But it is quite complex, and one reason doctors are now hesitating to prescribe long term high dose opioids in most pain patients.