Welcome Joyce. Today, the locks are fairly standard and your neighbor's keys will often unlock your trailer. I am not sure about the keys for a 1997 trailer.
Try the following:
A locksmith as suggested by mtnguy can replace the locks or possibly make keys.
Order new locks and replace yourself. This is very common and shouldn't be that difficult.
You might also want to review this thread which has some options that might pertain to you: Locks for the doors
I wish you luck. I'm moving this thread to General Tech and Repair. I think you'll get more exposure there.