Add article to product listing page

Can an article be inserted into a category page, in the upper part of the product listing page? Can it be done without adding other modules?

Hi,
If you don't to use a module to do that, the solution will probably be to use some customization code through the files of the "product" view of your front-end template via "Hikashop->Display->Views" but note that some development skills will be required.

But this customisation will be the same on all the pages of this type, and i want them diferent

So my advice will be to use modules so that you'll easily be able to control their displaying through the "module assignment" option of your module's Joomla configuration page.
Also note that by adding some PHP condition you'll be able to control where your customization have to display.