Why is my ear piercing still sore and tender?!?

I got them pierced new years eve, they are just normal earrings on my earlobes and they still hurt when want to switch my earrings out, when I put in some new ones it hurt cause the metal was rubbing inside my ear and it was hard to get thru because they are so tender and sore still, why is this? My sisters and moms ears were pretty much completely healed after week5. It's been about maybe 6 for me and they are really tender still...WHY.?