The door latches are adjustable at the "B" pillar. I would remove the striker from the "B" pillar and close the door to check for any interference. If the door fits the opening and the gaps are decent all around the opening, adjust the striker to latch the door. If the door can't swing full open to full closed with the striker removed, you have hinge issues or the cab is twisted.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy