What is meant by the phrase " We now dug into poor Clergyman's heart like a miner searching for gold"? Is it meant literally or symbolically or both?
Well, first, isn't the phrase "He now dug…"?
That aside, it is deeply symbolic, but it may also have some minor literal meanings. By that I mean, in Chapter 10 Chillingworth is mainly examining Dimsdale on a spiritual and moral level. It is therefore mainly spiritual. However, that chapter mentions a belief that odd flowers grow from a diseased heart (literally, in a graveyard), and Chillingworth does look at Dimsdale's chest at the end of the chapter, so there is some literal meaning there. Mostly, though, it is symbolic.