Hi Georgina
I would take the consultants advice and up the morphine,is he on a Slow release like Oxycodone,also paracetamol. Will enhance the Oxycodone, it takes awhile for the body to get use to these tablets,but if he is not on slow release,he will feel sleepy,slow release is a 12hour drug,so taken at 10 in morning and 10 at night helps.
If you cannot get hold of consultant see your GP. As consultants may not be the best person to help you manage the drugs and your surgery might be better situated with management of pain releave.
Myeloma effects the bones causing stress on Skelton,radiotherapy is either for pain management,or the danger of bones breaking,if you can not get an MRI scan,why not try for an ordinary exRay,which your own doctor can arrange,just in case the bone has been so weakened it might be collapsing.
If its just Myeloma pain the chemo regime,will make the pain easier in time as chemo works.,hope this gives you some help,you could ring the Myeloma help line and speak to Ellen or Maggi,by going direct,you can explain easier about it. Eve