DDJ-SX2 Jog wheels only affect pitch when a song plays

Not too sure whats going but every time i start a song, my jog wheels stop working properly and instead affect pitch, if a song is paused and i move the jog wheels it will work properly... Kinda confused and i've looked every where for an answer but cannot find one. I opened virtual dj and didn't have the problem in there but prefer serato for obvious reasons. Someone help please!