In bitcoin when you send your coins, your technically sending everything and it comes back to your change address. Does monero have the same concepts of a change address, because I see that in monero you only have 1 address that is reusable without impacting privacy.
Well, kind of. There will be a "change output" but it's not your address. In fact, Monero address works as an instruction to create many unique one-time public keys which actually holds the funds. Your wallet address never appears on the blockchain.
Each of those unique one-time public keys has a corresponding unique private key (which you can recover using your wallet's private spend key). THOSE work similar to Bitcoin address. So, when comparing with Bitcoin, it would be as if someone followed some instruction to generate a new Bitcoin address for you, sent the funds there, and you can auto-magically recover the private key and the sender can't :)
When spending, you're actually spending those one-time public keys. If, for example you have one of 10 XMR and one of 2 XMR, and want to send 11 XMR, the TX would create 2 brand-new one-time keys, one of 11 XMR for your recipient, and one of 1 XMR back to your wallet. Without some secret key, nobody is able to tell to which address those newly-created one-time keys belong.