I am still receiving "No Service"

Hello, I did an entire iPhone 5 teardown and rebuild. I have tried everything posted above, and I am still receiving "No Service" The iPhone recognizes when I remove the SIM card. I have tried different sim cards as well and resetting network settings. I do not know what is causing it to say No Service, but it is very annoying. EVERYTHING on this phone works besides cellular.

Since the charging port flex contains the cellular antenna I have recently looked around that area a lot. I will probably end up buying a new charging port assembly, but I want to make sure that is what is actually wrong. I have noticed the flex cable that wraps around the screw all the way in the bottom right hand corner of the phone it torn but still making contact (I am assuming that is what connects the signal to the frame?) and there is a flex cable that wraps over the top of the headphone jack that also got torn, but the headphone jack still works fine. So I am not sure what that cable connects too, and I do not see it in the part on eBay either. (http://www.ebay.com/itm/Black-Iphone-5-5...)

PLEASE help i have looked EVERYWHERE and cannot find anything to help!