Why am  I getting a lock Icon next to a channel; how can I remove it?

Thanks

.

When you are in the channel list, you will see on the bottom, what the colored buttons do.  RED if for LOCK channel.  When you have highlighted the channel in question, press the RED button "LOCK CHANNEL" and it will prompt you for the password.  Depending on your service, the password is "0000" or "1234" or other (but try those first).   If the password is correct, it will then ask you if you want to UNLOCK the channel.

That is assuming that the channel was accidently locked by you (accidently pressed red button to lock it as some point).  If it is flagged as an "adult" category, then that is done by the service provider.