I need professor permission for a lab class?

I talked to my counselor and I need to get into a psych 473 lab class, but apparently I need to talk to a professor to get permission to enter it. My counselor just said I need to send an email and ask. I sent one a month ago and got no response. I want to email a few other professors, but I think if I got ignored I must have done something wrong in the first one.

I introduced myself, explained my interest in their area of research, and asked if you they wouldn’t mind talking a bit more about seeing if I was a good fit. I kept it pretty brief because I know no one likes reading wind bag emails from people they don’t know.

Is this normal that I have to get permission to take a class required for my major (psychology)? Thanks.

Just send another request to the prof. A month ago may have been a busy time for faculty and a polite second request is fine.

How would you recommend I format or word the email?