Keeping your chain in good repair is important. If your chain is worn out it may bind or stick. It will also squeak and become loud when riding. There are several things one can do to fix this. Hopefully the chain is just dried out and needs to be lubricated. One can do this with a light weight oil. Just apply a thin layer over the chain and spin the wheel for a minute to get it worked through the chain. If that does not solve your problem then the chain may be bent and you would have to take that to your local bike shop to get that fixed. There are some things one can do to keep their chain in good working order. the first and most influential thing one can do is in the way one rides.
Cross chaining is when you are riding along and you are using a small gear in the front and a small gear in back, or a large gear in front and a large gear in back. The chain is supposed to stay straight. Cross chaining bends the chain sideways which is not the way it was made to bent. The best way to keep your chain in good condition is to avoid cross chaining and use your gears properly.