Can benign nodules and many calcified granulomas [seen on my new ct] create obstruction in airways and cause lung portions to collapse, ?

Unlikely: Benign pulmonary granulomas are an extremely common finding on ct of the chest, and almost never cause symptoms. A granuloma should never cause an airway obstruction. Other processes such as endobronchial mucus plugs or aspiration or a central mass lesion can cause obstruction and collapse of the affected segment.

Dr Khanna and another doctor agreed

Possible: Size and position of nodule can obstruct a small airway and create atelectasis( a type of collapse). Many folks have many nodules and no symptoms at all. See your pulmonologist to be sure this is not an active infection, or new module with malignancy. Serial ct scans are recommended usually. Stop smoking? Check allergies or dust, pets etc.