What is wrong with my park lock? Shifting Problems? on 2002 Chevrolet Avalanche 1500

I have a 2002 Chevy Avalanche Z71. So my truck is in park. I step on the brake and try to put it in reverse and it is really hard to put it into reverse, neutral, drive, 1st, 2nd, and 3rd. When i stop and try to put it into park sometimes it dosent go into park and i have to repeat trying to put it into park.
I think it is the park lock that needs to be adjusted. Im not too sure though. How much will it be to fix the problem?

Asked by for the 2002 Chevrolet Avalanche 1500
Sounds more like a binding shifter linkage - like a cable issue or something bent. It should be inspected at the transmission, and then inside the vehicle.
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sounds like your shift interlock system may be binding or sticking. If it came on all of a sudden, I would suspect a power or grround problem or perhaps a brake switch. It will require diagnosis before any accurate estimate can be provided.
I guess I can't be on my phone and have it show up as my username.