To ask is this a scam

[autienotnaughty]

So I keep getting emails from postmaster (the type you get when a email is undeliverable)
It say -
email to [email protected] is undeliverable due to mailbox being full. But the name is not an email in my contacts. I assumed it was an error of some kind.

Today I sent an email from my work email to my personal email and received the postmaster undeliverable email to my work email as though I had tried to send the email to 2 addresses mine and this other persons. My email received it no issues.

Am I being scammed /phished in some way.?

yes

An unsolicited email from hotmail.com?
Almost certainly

I would run virus scans and any other system scans you have on your devices, and do any system updates that are needed.

It may be that you have a virus that is trying to send itself on via your email program. Viruses can be used to gather data from your machine which could be used to try to gain access to any accounts you have online eg banking. It's unlikely but possible.

Or, it could be spammers who are using your email address as a fake "From" email when they are sending out mass spam emails to generated email addresses. The email addresses that don't exist will send the delivery failure message to your email address rather than the email address that they actually used. That's called backscatter.

Yes. Check your sent mail for anything you don't recognise. At best it's bad phishing at worst your email is compromised.

Thank you I suspected as much