When injected w morphine, instant hives, flushing. when i take vicodin, little rashes, itching. am i allergic, or do these types drugs just do this?

Avoidance: of those drugs or other drugs containing codeine, which a derivative of morphine, often times it is a side effect, not a true allergic reaction, but you cannot tell which of which, if you really need those drugs and have no other alternative consult an allergist/immunologist either yourself or through your treating physician, vheck aaaai.org or acaai.org for an allergist in your area, goodluck