[quote=Paul Warburton]What do you mean you fret with your left hand..first off, our basses have no frets..and, unless you're a lefty, everbody fingers with thier left hand.

QUOTE]
yes. problem #1= if it has frets, its not a double bass!
but seriously, listen to these guys. the pressure you use to depress the strings needs to come from you body weight, not from your muscles or from clamping with your thumb. check youself to see if you are clamping, that used to cause me alot of pain