Hi,
If you use the "tabular" layout page instead of the default one, you should get a "description" title for the description. You can configure that option under the Display tab of the configuration.
Otherwise, you can also edit the file "show_default" of the view "product" via the menu Display->Views and add your text before the description display block of code:
<div id="hikashop_product_description_main" class="hikashop_product_description_main">
<?php
echo JHTML::_('content.prepare',preg_replace('#<hr *id="system-readmore" */>#i','',$this->element->product_description));
?>
</div>