Hello and welcome.
If pulling back on the shifter used to work, but now does not click, then i would suspect that the shift cable needs adjustment.
If it does do that click, but still wont turn, then i would suspect a problem in the ignition key cylinder. Sometimes sprying WD-40 in the cylinder would help. Spray in and turn the key back and forth quickly. This may fre it up for awhile, but eventually will stick again. This would incidate the cylinder needs to be replaced.