My wife has a '99 GS400, when she got home from work today she turned the car off before she put it in park and now the shifter won't move without depressing the shift lock override. some help would be appreciated

hi, and welcome to LOC!

That's actually the behaviour I'd expect - use the button to put the car in park and then when you start the car the shifter should work normally again - on mine the car won't start either unless the shifter is in park which worried me the first time it happened and I didnt realise what I'd done!