Is my mosfet burned out?
Well, either you are measuring the body diode, have a short somewhere else, the MOSFET is turned on with Vgs > Vt, or the MOSFET is failed short.  If you have removed the MOSFET from the circuit and you are not measuring the body diode, then it is failed short and you need to replace it.  And I presume you mean source and drain as 'collector' is for a BJT.