You use a video tool like Premiere Pro....
Welcome to the forum.
Do you mean that you cannot play back your timeline, and both see the Video and hear the Audio?
Do you get playback of either the Video, or the Audio, or neither?
PS - Mylenium's suggestion for Premiere Pro is a good one, as it has full Video and Audio capabilities, and is the best tool, if one is doing much video-editing, beyond small Projects. As a side note, if one buys the Production Premium, or Master Collection, then they also get Adobe Audition, a full-featured Audio editor, and it will interface well with PrPro.