Receiver pin holes out of round.

Hello everyone.
I have a 2010 Chevy Silverado 1500 with a tow capacity of 9200 lbs.
My trailer is a 31' Tracer Touring model lite. Empty, it is under 7,000 lbs. Loaded, at most would be less than 7700 lbs. We carry little food, buy once we get to a campground. We basically carry cloths, 15 gallons of water, and chairs, sewer hoses, and water hoses.

I have never put this combo on a scale.
Before going on a 1000 mile round trip vacation this year, I noticed that the pin hole on one side was slightly out of round, at the bottom of the pin hole.
Today, while pulling the hitch out to put it in the garage, I noticed the hole has gotten larger and the other side is starting to get slightly larger.

I have a Reese WD hitch, with the Trunnion Bar setup.

I want to put on a new receiver, but before I ruin a second one, wonder if anyone has any input on how this is happening?
The receive came new with the truck and is a class IV. It is code VR4 on the options, can handle 10,500 lbs with the WD set up.

We followed the instructions when we first set it up, and it towed fine. We didn't tow last year, and I don't remember which link the chain was pinned at. Could I have made the bars too tight this time around?

Any input would be appreciated.
Thanks,
Rich

If you are discussing the holes in the receiver becoming oval it is from wear. High end receivers have an extra layer of metal around the holes to keep that wear to a minimum. Torklift (and others) make higher quality receivers than was OEM on your vehicle. You might check them out.