Truck turns over but won't start, why? on 2006 Dodge Ram 2500

I was told by my transmission shop that my ECM was going bad because of shifting issues (tool long out of first and not at all out of 2nd). It had been hard starting more than usual before the shift problems. then the shifting seemed to "fix it self" but now it wont start at all...

Asked by for the 2006 Dodge Ram 2500