What is a gold key worn like a necklace surpose to resemble?

The dream goes like this…

i was with a person who i use to play with as a small child and i havent seen that person in years. She is female and i am male (just to clear that up). I wont explain the whole dream but, we went to a department store and she bought a gold key necklace. She is rich by the way. But she was 1000 yen short though, or didnt have a 1000yen note (i am living in japan at the moment so all my currency is in yen). 1000 yen is around AU$15 anyway. So i told her that i will give you some money for it.
i put down a 10,000 (AU$150) yen note and she gave me some money in return.

I woke up at this point because i set my alarm, however during my next dream (which i cant remember clearly, unfortunatly) i was carrying this gold key necklace with me everywhere (in its case)…

What is this necklase surpose to mean???

edit//
also, about a week before this dream i recieved a key from someone in rl for not particular reason… he just gave it to me. I have no idea what it opens though or why he gave it to me…
mabey this has a connection?