This is probably a silly question but is there a horizontal scrollbar that has to be enabled in Okular? I tried looking around, but I cant resolve this issue.

Im talking about the Contents on the left panel. The entries in the Contents Panel are all truncated and I have to resize the left panel all the way to the right just to see the whole text entry. Is there an option where I can enable this?

Thanks...

There's no such option for this; although, entries have tooltips (so you can read them even without stretch the whole sidebar).