URL Path Changes When in Category/Archive

Hi,

I’m having some problems with the URL/paths whenever I go to the Categories or Archives page. More specifically, whenever I go to those pages, the URL/path of my navigation link changes.

i.e.
My about page link goes from mywebsite/about
to mywebsite/category/about.

The same thing applies to other links as well in that ‘/category’ is attached to every URL.

I’m not sure if the following info is relevant, but I manually coded the links to my pages (I coded the links in the sidebar.php file). Is this causing the problem? If it is, what can I do to fix it while retaining my manually coded links?

Thanks!