How does "sore throat" phrase refer to "report to cop"? Is it an idiom?
Native speaker’s answer
Rebecca
This isn't any type of idiom or slang. The backstory is that the man that Deadshot is targeting used to be a gang member. But now he's turning himself in, to the cops, and a member of the gang (man speaking to Deadshot on the phone) wants him dead. So, Deadshot is saying that the target is about to give up so much information ( compared to singing) that he's gonna get a sour throat.