"Lack of pain relief"

Similar to another story I have just read my mum was admitted after a fall and had to undergo an operation as she had fractured her hip. After the operation the doctor said they would ensure that she was comfortable and would not be in any pain and told me what pain killers he had prescribed. A short time after he left my mum started to suffer and she has a very high pain threshold having lived with crushed vertebra's for many years, I knew she was in pain. I went for a nurse who said she would be in shortly, 10 minutes nothing, I went again and she said can I help you as if she never seen me before again I explained and she said the same. A further 10 minutes went by and still no sign so I went to see her again and I wasn't moving until she did something. She said I'll have to check the system, I'll give her some paracetamol, to which I replied that would not work as mum already takes Tramadol for her existing pain. I also explained what the doctor had said but she was quite sharp with me and said they don't now the pain procedure and we have to start with paracetamol and take it from there. I can appreciate there is a procedure but that's ridiculous when 1 - she had just had an operation and 2 - she was used to stronger medication anyway. I also appreciate that the nurses are busy, but half an hour in pain is a long time and I worry what would have happened if we hadn't been there?