Hi, welcome to the forum, your history is suggestive of that you are having drug allergy to
morphine. Some patients have reported to have
itching (in more than 10%), rash and development of hives.
The possibilities for allergy are due to presence of Phenanthrene in opioids. You can even develop hypersensitivity reactions to other phenanthrene derivative opioid agonists (codeine, hydrocodone, hydromorphone, levorphanol, oxycodone, oxymorphone).