Why won't my 01 Dodge Ram 5.9l run after its warm

You are correct it is a turn over no start and I've depressed the pedal and tried it has no effect and I've had a mechanic do a diagnostic and it says that the asd relay or pcm is malfunctioning I just want to know if it could possibly be anything else before I have the Pcm replaced

First, I would think that is too quick a jump to the PCM, too many other things might cause this problem. My advice would be to ask the mechanic: if you authorize this repair, does he guarantee that it will fix the problem? If not, he is guessing, and you are at the wrong shop. Further diagnosis would be recommended if mechanic is unwilling to guarantee the fix.