"Bad EGR valve"

I went to a mechanic last winter due to something leaking from my 2014 Jeep grand Cherokee Eco Diesel, The mechanic told me I had a crack in my radiator. I went to a jeep dealership near me and asked them to check over the car and see where the leak was coming from. (Keep in mind, my car never had any heating issues and never threw any codes prior to this fiasco I'm going through) This jeep dealership informed me that I have a crack in my radiator. I have them change out my radiator and my hoses.. Not even 24-48 hours after having them changed out my check engine light pops on. I bring it to get the code read and its a p0128 code.. I go back to the dealership and tell them my check engine light came on.. The dealerships tells me my thermostat is bad, I tried racking my brain as to how the thermostat just goes bad after I get my radiator and hoses changed. The dealership service techs were completely rude and unprofessional so I bring it to another dealership and explain my story. They check over the car and tell me it is in fact my thermostat. I then spend hundreds of dollars to get my thermostat changed. 24-48 hours later my check engine light is back! Bring it back to the dealership, they go over my car again and tell me " your PCM is bad" .. 1000 dollars later, I change out my PCM. Yes, the story doesn't end there.. My check engine light is back on. The dealership contacts Chrysler and Star, which then a case is opened up. I get a phone call a day or two later stating that my EGR valve is bad and has an internal crack, after questioning the dealership they admitted that they missed diagnosed the PCM being bad. I'm up to my eyeballs in bills with this jeep when in reality the jeep never had any codes thrown before this... Did the first dealership mess up? Does this sound familiar to anyone.. Could my EGR valve even be bad. How does this all stem from the radiator to the thermostat to a bad PCM to my EGR valve being bad????