Since the resistors all appear correct I would start checking for offboard problems. Make sure that the potentiometer is a good one and 100K. Also make sure nothing is shorting out. In one photo it appears that the volume potentiometer is up against the guitar cable for example. That may not be it but make sure everything is in order when testing. The Volume pot needs to be up all the way to not attenuate the circuit. Sometimes the cheaper pots we all use contain a bad egg. Check the battery voltage. Check the transistor voltage. After all that reflow the project and report back. I hope that helps since it is a fairly simple project I suspect something offboard.