Q&A

Definitely way overdue for plugs-I've never had them go beyond 80K.Replacing them would be the first step.If it still runs rough after that,it is likely to be the coil.
Whether it is hard or not,depends on your mechanical skill and experience.One needs the proper tools,a sense of how tight to make them,as well as knowing that a bit of anti-seize should be applied to the threads.
As indicated,the fronts aren't too bad to do.The rears can be a bit daunting,since several parts have to be removed or disconnected.

codes read said coil misfire- primary/secondary multipolar misfire- 2-3 misfire

It still could just be used up spark plugs. Replace them first and see if the engine runs normally. If not, thie spark plugs ignition coils will probably need replaced on cylinders 2 and 3.