Nursing 101
Pain is a pure subjective symptom. One can examine, and try to determine if the person has pain and where it is coming from, but unlike say a fever or heart attack there isn't a certian clinical test to say "yes", this person is in pain.
Thus medications are dosed based upon assessement and reactions. However someone keen to get their hands on medication for pain for other reasons can often "fool" the most trained health care professional. It does not help that for years pain meds, even before such substances as morphine, and other powerful, but highly addictive durgs could be obtained without a doctor's consent.
To crack down on what the United States government felt was too many drugs being misused and diverted, there has been a concentrated effort to charge and prosecute doctors and others who "abuse" script writing. Every doctor, nurse and such knows the classes of addictive pain medications, and work to strike a balance between treating pain, but not allowing the patient to become "hooked", however again it is hard to tell when a person is truly in pain or just looking for a fix. I could whack your hand with a mallet, and you could not utter a sound, much less flich, but does that mean you are not in pain?
What has resulted from all the legal and judical prosecutions of doctors and nurses, is that many are loathe to give out anything stronger than Vicodin (Schedule II version) or similar mild pain medication. You can forget getting Percodan or any of the other real powerful pain meds unless one is terminally ill, and even then.
Problems with OxyContin diversion is the most recent of a long list of problems of good pain meds going to bad purposes. The result of which means those really in need of the medication have a very difficult time obtaining it if at all.
Despite my post above, when you have 70 year old grannies filling their scripts for OxyContin, then selling the pills, things are bad.
The other problem is today far more home care goes on than in years past, well say since modern hospitals began replacing being cared for at home. Today one has persons suffering from all manner and sundry of illnesses and diseases being cared for either in their own homes or in a home like setting. This means all their perscriptions, including any Scheduled II,III or higher drugs are not locked in a cabinet at the nurse's station, and subject to counts and verfication. Anyone in that household, or access to it can get at those drugs, this includes the home help.