problem with audio

I have cubase Le4 installed with Lexicon OMEGA.
My guitar seems to be working fine. But i have an issue with my inserts. I cant hear any inserts i add to a guitar track
If i add distortion, chourus, flanger ect. It cant be heard while im adding it to tje track.
So my issue is i cant play my guitar with the vsts cause when i play it all sounds clean.
However, when i record on the track the inserts ARE there. I just cant hear them while i play/edit my distortion.