Background color under text only

I am trying to get a background color that follows the text only and not the width of the div or whatever.

I am using wordpress. I set up a span in the content.php, and removed the p’s from pages. Then it works and the code is something like:

<div class="entry-content">
<span>
my text...
</span>
</div>

But I need the p’s in pages… And if the code is like this it doesn’t work..:

<div class="entry-content">
<span>
<p>
my text...
</p>
</span>
</div>

Is it only with span I can do this?

Would appreciate any help or advice.