The 2 things are not related outside of the fact maybe when they were under the hood they damaged or loosened a plug wire. (actually for this job the hood does not even need to be opened.)
Driving with a missfire is very damaging to the coil pack.
Not only that but when the missfire is happening you are dumping unburnt fuel into the cylinder or cylinders. This washes the walls and rings (possible damage), contaminates the oil (possible bearing damage), and floods the exhaust (possible O2 & cat damage)
Get the problem fixed ASAP!!!
