Call your local pharmacist and ask them. They should be able to give you an answer. I did that, because I have other allergies and was worried. I just told them that I was going to be taking Delatestryl and deca durabolin for medical reasons and I needed to know if I was allergic to them. There is also a website (online pharmicist) which you can email and they will email you back within 24 hrs. Hope this will help.
Where did the pop you? I had a penicillin shot in the glute once as a precaution when I cut my self (accidentially) and they used a HUGE pin. I'm talking like 18 gage and 2.5 inches long. Right after the e-room doc popped me, he left. I rolled up onto the gurney and almost passed out (got all sweaty and shit.) I think it was the needle and not the antibiotic.
I am allergic to penicillin and take steroids with no problem. That doesnt mean that you wouldn't have an allergy though. Each person is different, but I have never heard of allergies from the two substances being connected.