Make sure you havent turned off the Internal speaker, or if you have an external speaker be sure its plugged in, wires not been cut etc, be sure the SQUELCH is turned down lowest setting, volume is up...antenna SWR is correct, make sure you havent activated the PA circuit or something silly....look for a bad connection on your mic cable, or Antenna cables.....if you were operating it and the SWR was high and you never tuend your antennas you may have burned it out, time to find a shop.
Try connecting it to someone elses antennas or truck.....Radios can be affected by water, shorts, a voltage spike, sounds like a trip to a repair shop is in order or buy a better radio...