I guess take it out of the case and see if the problem persists.
If the problems stop it's shorting on the case somewhere.
If not it's something to do with the PCB itself I guess.
If it's a short with the case and you've still got that rectangular piece of foam from the packaging you can try sticking it between the PCB and case.
Shelf liner will work too. If it's the PCB a photo will at least give a hit of whether it's your soldering or something else