Hi Hon,
So sorry to hear that you are still in pain.
You may well have tried all this but just some information for you. Morphine is a strong pain relief, it is centrally acting (acting on pain receptors in the Central nervous system), and the effect of such opioid drug varies from patient to patient, and also varies, depending on the site/ cause of 'injury'. Aspirin, paracetamol and NSAIDs (non-steroidal anti-inflammatory drugs), act peripherally (i.e. at the site of the pain), and can be just as affective, and sometimes more effective than morphine (again depends on the patient and the nature of the pain). Paracetamol is being used more and more in UK hospitals, as it is a very effective pain relieving drug. The anti-inflamatory actions of NSAIDS (such as ibuprofen) could make all the difference to you, since you may fell have some swelling and inflammation following surgery, which could be the main cause of your pain (but please check with your Doc, or pharmacist first).
There are also other anti-emetics (anti-sickness) medications available other than metoclopramide (which I believe is the drug you had an allergic reaction to?). Some of which act completely differently and are in no way related to meoclopramide, so it may be worth asking if there is another anti-sickness drug you could take instead. Also morphine, and other opioid drugs are available in 'rectal' form. I agree this might not be your first choice in methods to administer medication, but if it works - hell, why not?! I believe it's a bit hit and miss (location-wise), as to whether rectal opioids are available, but that would completely eliminate any nausea /sickness issues, and a need for an anti-emetic drug, and allow you to have full doses of pain relief.
Morphine is also available in patches (like nicotine patches), which, while generally used for more chronic / long standing conditions may (don't know?) benefit you in the short term.
It goes without saying, that you should take professional advice before changing your medication, but perhaps there are other meds you haven't tried or a different administration of drugs that could help you in the next few weeks, and after your next surgery.
I don't like to think of you (or anybody) in pain. We are all individuals, you especially;), and sometimes we have to go outside the box to find a solution. My personal opinion, in this day and age is that no-one should suffer pain unnecessarily.
CB x x x x