1997 Buick Park Avenue Ignition keyy question

While it's not normal, it does happen from time to time.
Either the key was cut in such a way that there are not any pins that hold it in place, or more common the lock and key are getting worn out.
So
you can get a new lock and key.
Or just remember to make sure you are in the LOCK position before you remove the key.
I'm sure after a few weeks, it will be second nature that you are in the correct position before you take out the key.

Something you might try.
Take your title, or insurance card, whatever you have to prove that you are allowed to drive the car.
And your photo ID with you to a GM dealer.

Starting in about 1995, GM kept track of the key codes.
And a dealership can cut a brand new key from your VIN. And not simply make a copy of a worn out key.

Also, some one that has experience at cutting a key manually (meaning that they don't have an automated machine do it for them)
They can simply look at the key and read what the cuts are supposed to be.

A customer once locked their doors, with their keys laying on the seat.
It took me two tries, but I was able to cut a new key by looking through the window at the old key.

About the trunk lock, it may just be dirty.

here's probably way more info than what you ever wanted.
2-A.
The pins are not falling into place.

You kinda need to know how a lock works for this part.
Look at a key and you will see there are different depth cuts in it.
Those different cuts correspond with different length pins in the lock cylinder.
See how the red pins are of different length?
But with the key inserted, they are all even with the blue pins.

When the red pins are held in the correct position by the correct key, the spring loaded blue pins are flush with the outer housing of the lock, and the red pins are flush with the inner cylinder of the lock
And thus the inner cylinder can be rotated.

If debris such as pocket lint, ear wax, or just plain old dirt gets into the pins and causes enough friction for the spring loaded blue pins to not be able to push the red pins back in place.
Then the red pins will be partially stuck in the hole for the blue pins and the cylinder can not turn.

Putting the key in the lock and then tapping on it with a small hammer may help until you have the chance to have the lock cleaned.

Do an internet search for the word "bump key" if you want to know more about how a lock cylinder works.

2-B.
The same goes for if a key is worn out.
If a key is badly worn, then it will not put the red pins in the correct spot and some of the pins will keep the cylinder from turning.

If your key is worn out, try a spare if you have one.
Or put the key in and "Jiggle" it while trying to turn the lock.