After installing google webmasters tools it seems I have duplicate page titles. I suspect these were indexed when I was deciding which theme to go with and how to generally get around a wordpress theme.
Two of these page titles include a category keyword phrase that is important for my niche( they are static pages). The two pages still exist and I have retitled them but they still include the target phrase. I even modified the page URL to be different from the old one and still include the target phrase. To no avail, webmaster tools still tells me I have duplicate page titles.
There are two more pages, home and about which dont exist on my site as i had delted them.
How detrimetal is this to my site and is there any way to fix it?