it's already explained why dean wears that ネックレス (it's from sam). is there any explanation why dean wears that ring on his right finger?

I think John might have gave it to him because he seems to look after it as much as his necklace! So it must mean alot to him. :D x

Not that I know of.

I know that's it's a bottle opener .. like for ビール bottles and stuff. ;P but i'm not sure if it has some sort of meaning または not.