Need help, Camaro problem
 

Well today i was driving and my service engine soon light blinked on and off and finally stayed on. I went to to Auto Zone to get a diagnostics on it. They said there were multiple misfires, something was wrong with the air recirculation which he said maybe because the EGR is jacked. Also, something was wrong with the passenger side catalytic converter. The car is running fine. What do i need to do to have it fixed and how much do you think it will cost. Also does anyone have any ideas what caused this? Here is my list of mods
Asp crank pulley (just installed)
slp lid
bored out maf sensor
air temp module
hypertech thermostat
fernco mod
cut out
throttle body bump stop mod
free ram air