Talking to your child about fears can be a slippery slope because you could inadvertently reinforce those fears by giving them attention. On the other hand, you don't want to ignore your child's fears.
It's a good idea to set some parameters when talking about your child's fears, so they have opportunities to manage some of their distress. Establish a time to talk about the fears, but make sure it's not at bedtime; that tends to be the time when a child's imagination can run wild and fears can snowball.
For example, establish a time to talk — say 5:30 every afternoon. Then, tell your child to write their fears down as they occur and you'll talk about them the next day. Over time, you'll begin to see your child managing some of their discomfort independently, and the overall volume of fears will begin to decrease.