My key won't go into the car door lock?

[Rachel]

I have a 2005 Honda Accord DX value package, so i don't have automatic locks. When I tried putting my key into the lock on the driver's side, it wouldn't go in. I didn't want to force it, but i tried pushing it and then it just got stuck and I had to pull it out. I can't even get the key into the lock. I'm bringing the car into honda, but was wondering what do you think the problem is? and how much do you think it's going to cost me?