Can Pain Killers Be Taken Along With Metronidazole?

First question: I am on oxycodone and was just prescribed metronidazole (in pill form) for a bacterial infection. I have been told by my doctor and the pharmacist not to drink any alcohol during the treatment, that I would be come very ill. Will the pain killers do the same thing that the alcohol does when combined with this antibiotic or should I be ok?

Second question: I just had a colposcopy done and was told not to have sex, use tampons, douche, etc for 7 to 10 days. Is it safe to use the gel form of metronidazole during this time or should I wait?