Q: oil pressure switch

The "apparent" oil pressure switch malfunction is not a cause of the stalling or misfiring. That malfunction with the switch has to be diagnosed and confirmed because sometimes there is nothing wrong with the switch itself but rather there is a fault in the wiring or connections to the switch. Also, depending on the circumstances, it might have to be determined if the oil pressure might actually be low using direct gauge measurement. So that all has to be checked out by a certified Mechanic. If it turns out the switch is bad, YourMechanic does replace oil pressure switches and you should get an estimate because you might save some money.

As far as the repair service that should be requested, and estimated, to resolve the misfiring and stalling, the repair needed will depend on exactly what the causes of the misfiring and stalling turn out to be on diagnosis. If you request a misfiring diagnostic(https://www.yourmechanic.com/services/engine-is-misfiring-inspection) or a stalling diagnostic what the certified Mechanic will do is go through the list of possibilities (it looks like a "decision-tree"), after downloading trouble codes, of course (you indicated the check engine light has illuminated so there are trouble codes and that will be helpful in the diagnostic), until the underlying root cause(s) is found. Once a firm diagnosis is in hand, that accounts for the symptoms you report, the mechanic will explain exactly what has failed and, of course, the cost to fix the failure.