Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
In a large frypan, cook pancetta in oil until just beginning to brown. Stir in eschalots, garlic and mushrooms: cook for one minute. Season with pepper and oregano and pour in chicken stock. Bring to a boil over medium-high heat and simmer for 1 to 2 minutes, stirring occasionally. Cover and continue to simmer for 5 to 7 minutes.
Strain liquid from pan into cooked linguine and add olive oil. Toss to coat. Divide pasta onto individual serving plates and top with equal portions of pancetta and mushrooms. Garnish with freshly grated Parmesan.