It sounds like you may have had a chimney fire, especially if you've been experiencing fires frequently. The piece of metal that fell could be a damaged chimney liner or a part of your fireplace system. It's good that you have a repair guy coming; they'll be able to assess the situation properly. In the meantime, it's important not to use your fireplace until it's been inspected and repaired to avoid any further risks.

It's been a while since your post, but I'd like to add some information.
I'm sorry to hear about your fireplace falling apart – that sounds like a real pain! Dealing with home repairs can be such a hassle, especially when it's something as important as your fireplace. Have you thought about reaching out to professionals for help? I've heard good things about https://nationalchimneysupplies.com  – they seem to have a wide range of products and expertise in fireplace repair.

Sometimes it's better to invest in getting it fixed right rather than trying to tackle it yourself and potentially making things worse, you know? It's all about ensuring your home is safe and cozy for the long haul. Wishing you the best of luck in getting it sorted out soon so you can enjoy those warm, crackling fires again!