On most cars disconnecting the battery for a while will shut off the light, but the code may remain in memory to be read with a scanner. The light should only come back on if the problem still exists. So disconnect and see if it comes back. If it does, then somethings up.
Disconnect the battery to reset the CEL, if CEL turns back on have it read at Autozone of wherever that will read it for free. I would check the oil level if you had it changed by someone else, these require eight quarts to refill. Sometimes that can slip by these "oil change technicians".
Much easier than disconnecting the battery is to go in the fuse panel under the hood and remove the EFI fuse for a couple of seconds. Does the same thing and you don't have to reset all of your radio stations.