Please help me with the meaning and usage of these words/phrases.
Bang go/Bang goes
I have heard them somewhere, but am unaware of their meaning and how can i use them in sentences and in which contexts?
Of your three examples, the only one I'm familiar with is "talking shop." This means to discuss work or things that happen while on the job.
For example, Fred and Brian are both engineers who work for an automotive company. They are also friends, and they meet for dinner one evening and bring their wives along. During the meal, Fred and Brian keep talking about problems with a particular design, and how their supervisor is wrong, and how co-workers aren't cooperating, etc. Brian's wife finally says "If you two are going to continue to talk shop all night Mary and I are going to leave you here and go see a movie."