Do you get a new key when you replace the ignition switch

the spring broke or has something in way(debris/corrosion)or tumbler worn and sticking can try spray graphite in tumbler might free up or will need to replace switch

the tumblers in the key switch maybe worn and require replacement. the key tumbler assembly will come with an new key.

I suggest a locksmith be called in to remove the barrel
he will be able to supply a new barrel and cut the key to suit what you have and set the tumblers to the new key

The reason that the key wouldn't turn must have come from a malfunction of the ignition switch or the connecting rod, rather than the just the tumbler. Since the dash lights & gauges work now, at least part of the ignition switch is working, but apparently not the part that's engaged when the switch is turned to the "start" position.
By replacing just the tumbler, the dealership tech would have jiggled the connecting rod just enough to reseat it (and fix the jam that was causing the key to fail to turn in the tumbler), but didn't fix the real problem, which seems to be a worn out ignition switch or worn connecting/actuating rod.

Here's your steering column anatomy - illustration courtesy Ford Motor Company.

look at your key if its worn down try another key if both keys are same way than u will need to replace the ignition cylinder not the switch these are 2 units which are attached, the tumblers are in the cylinder--- u can have the cylinder re done[new tumbler ] diy u can take out housing and bring to dealer saves on labor or if have local bone yard buy housing [ignition ] with key take out cylinder and replace with new junk yard part about 15-75 bucks a lot of the u-pull-it are the cheapest 15 for whole system---dealer to redo cylinder[tumbler replacement] with u bringing in housing 100-200---if cylinder also damaged add additional 100-- call up parts person and get prices tumblers/cylinder/whole unit good luck

It isn't the steering lock?
If not, please check if you have a spare key. Does this work in a single shot? Then copy that key and use that.

was the ignition switch getting hard to turn with the key for a while or did this just all of a sudden happen usually the problem has been going of for a while but people just ignore it until it gets to this point,it sounds like the tumblers in the ignition key switch have gone bad and the tumbler assembly needs to be replaced,the new tumbler assembly can keyed to the original key if the key is not worn out.this should be replaced with a new key if it is.

Possible fix for the year of car is a worn key or tumbler or both. Check with Olds with your car vin number to cut a new key. If it's the tumbler, it will have to be re-pinned with new pins by locksmith or replaced with new tumbler. Rare occasions the turning of steering wheel frees the steering locks pressure hold on ignition tumbler. New tumbler can be reset to match door so as not to have two different keys.

ignition switch tumblers are worn and will have to replace the switch, which will come with new keys.

sounds like the ignition itself is worn,go get one from a scrap yard and replace it