chevy kodiak diesel

I have a 07 Chevy Kodiak duramax diesel, it wont start, it quit running coming off the freeway, it seems like its not getting fuel, I primed it and tried at least 20 times to start it but it will not start, I got a code reader but its not showing any codes, prior to this for the past month or so the truck would run fine and then sometimes when you shut it off you would have to prime it to get it started again, but it was easy to prime and had always started again, I called the shop and they are saying injector pump? I’m not sure, and I really need my truck up and running, please can anyone help me out? I may need a more detailed answer as I’m a girl (not afraid to get greasy) I do know the parts of the motor so if you can talk me through it, I have the tools and I can follow through, I really need to get this truck going.