Is there any way of seeing whether I have responses in either main or meta, without having to open up two different user pages?
Responses specific to you across all StackExchange networks is usually available from your StackExchange Inbox. This includes responses to your comments, comments to your questions/answers (even if their not directed at you), chats or answers in general.
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or accessible by clicking on the StackExchange drop-down menu in the top left of the browser and selecting Inbox.