I have a little problem my back hatch will not open I put the key in the key hole but it will not turn left or right. the only thing i can do to open it is press the hatch button in the interior.

 

It's possible that either the hatch lock or the door locks got changed at some point and your key only works for the doors.

 

Well before your button stops working pull the lock outof the trunk and take it into a locksmith, he can make a key or just read numbers off lock and make one.

But you need to remove the lock first, they charge 3 times more if you don't.

 

Did you check your key to see if the bumps on top are worn or rounded? If so you might need a locksmith, because the tumblers might not be moving to the right positions.

 

I would try spraying some lube in the cylinder first. It may be frozen from not being used. If it doesn't work, I would pull the lock and have it re-keyed to match your existing door key. Call a local GM dealer or a locksmith and see if they do it there. For a reference, I charge $45 at work to re-key a cylinder.