It's not a systemic problem, not inevitable, but its widespread!
For patients having surgery the anaesthetist will write up proper pain relief covering the options from paracetamol, anti inflammatories, up to weak opioids such as codeine and tramadol , up again to morphine, including patient controlled administration of that - a sort of pain ladder, if you will.
In big units they work closely with pain control nurses, and they are available for non surgical patients too if asked - these people are experts on the "pain ladder" approach from simplest to strongest
But in general wards, and for general patients, there's a reluctance on the part of senior and junior doctors to use opioids, somehow thinking they are not for general use, but should be confined to surgical and cancer and dying patients - they don't seem to realise that prescribing should match the severity of the pain rather than a particular diagnosis.
As for the bit about patients only getting pain relief if they ask for it, that's basically true as nearly always the pain killers are prescribed "as required"
For patients in pain the nursing plan should involve asking the patient at frequent intervals if they have pain, and be asked if the administered drug has worked
This can be okay if the patient is sensible and in control of their faculties and can ask the right questions and give the right answers to the questions when asked about effectiveness
But not all patients are capable, and I have to say not all nurses/care assistants ask in the right way or respond in the right way either.
Controlled drugs are not easily used in general wards - it can take two trained nurses up to half an hour to go through the process of giving a single dose - having to check the patient, check the drug, check the stock remaining, administer it, and sign it all off - so its very demanding on resources when times are busy, so maybe there's always some reluctance to use them.
Hospices are much better as a rule, but that's as much to do with resources as to do with skills or compassion - remember a hospice might have as many staff for their captive, stable population of 6-8 patients as would be there to run an acute ward of 30+ patients with loads of admissions, discharges, patients going to and from theatre etc - and acute wards can have 6-8 patients with much the same issues as the hospice ones in among the hectic activity of acute work.
So its not easy at any level.
And often it's the case -and it should be like this - that the patient or an informed relative on their behalf has to keep asking the questions and asking for help - nobody likes to feel they are being complained about or complained to!! but sometimes its the only way.
Asking for more pain relief, or having to ask "if you can't give me something can you find someone who can" is not easy but can be the only way.