What is this tiny pinching pain?

Right I have this tiny little pinching pain in the middle of my little finger. It's really starting to irritate me and when I touch it to see if anything has been caught it in, it feels like someone is scratching me with a needle. There's nothing there, no cuts no splinters, nothing. So I don't know what it is. Any ideas? It started late last night and is still there, how do I get rid of it?