After accidently dropping my bass
it now seems to make on odd screeching noise when it wants to, like a truck's airbrakes squealing to a halt, but tinnier, and it goes away when l turn the bass's volume down, it is a passive squier p bass, l've tried different chords, l tried using my guitar amp (low volume of course), l've tried messing with my eq on my bass amp, l've even tried playing through my stereo, but it still comes through. Sometimes when l move into anouther position it goes away, and when it's not acting up and l hold the bass in front of the speaker, it does nothing, so feedback seems unlikely. l'm out of ideas here, can someone help?
Strange noise problem 
