Can't Remove Hitch Pin, Not Rusty

[My Brothers Taho]

I towed a (5 x 8-ish) single axle trailer 5 miles loaded with a Case 222 lawn tractor. It appears that the hitch flexed, and the formed end of the pin rotated down into the slot for the safety chains.

Is this a "normal" thing? Is the hitch that flexible?

I should be able to get it out by removing a little material from the end of the leg but do I have to?

 

[Grady_Wilson]

From the looks of the first picture, the pin was much smaller than the hitch pin hole.
It allowed it to move up and down, along with allowing the hitch to move inside the receiver.
This caused the pin to move upwards during the movement of towing and get inside the safety chain loop.
I would see if you can lift the hitch bar enough to move that pin up to rotate it out of the loop.
Or, you could just cut the pin and source the proper sized pin for the receiver.

 

[OR VietVet]

Wiggle and tug. The hitch flexed enough at one time during the tow and allowed the movement. Lots of rust there. The second pic looks like could easily use a pry bar out of your tool box and pop it out. Plus, like @Grady_Wilson said, check that pin size when you get it out.