The phrase "a difficult job in" is correct and usable in written English.
It can be used when describing a challenging position or task within a specific field or context.
Example: "She found a difficult job in the competitive world of finance."
Alternatives: "a challenging position in" or "a tough role in".
The government has a difficult job in deciding what it can achieve in the negotiations.
Cameron admitted it was inevitable that the government would face a difficult job in stabilising the public finances.
Mr. Holder has a difficult job, in which the ever-changing "art of the possible" (that is to say, politics) intersects with the eternal demands of justice.
To be fair, the accounting rules give the firms a difficult job in evaluating a bank's estimate of fair value of securities that rarely trade.
The next mayor will have a difficult job in rebuilding trust in communities scarred by racial profiling in the stop-and-frisk program.
European governments are trying to win back the confidence of bond market investors by reducing deficits, a difficult job in a slowing economy.
Helping young people learn is a difficult job even in the best circumstances and, in the areas of greatest need, it can be onerous.
One of the reasons could be that synthesizing silver NPs with repeatable size is a difficult job which in turn affects its optical properties.
Introducing a horse to a rider has, throughout recorded history, been a difficult job, involving, in effect, breaking the animal's spirit, and taking months or even years.
We know we are only halfway there and we have a tremendously difficult job in a fortnight's time.
"But equally we know we're only halfway there, we've got a very difficult job in a fortnight's time".
