I've had pierced ears for over 15 years. I've never had any problem until about 5 months ago, I tried to wear earrings with a screwdriver-like post (tiffany's) and I forced the earring on my left lobe just a little too much. And since then, i've had pain whenever I try to wear an earring on my left ear (since its only on my left lobe, that rules out allergies of any kind).
I use neosporin and bactin at times to ease the earring in, but after awhile my left ear starts hurting, and the pain spreads, at times to my inner ear.