Lifter or fuel injector is the most likely source of a tick.
Since you probably have an overhead cam removing the valve cover and checking for play might be a good idea.
Check oil pressure as well.
Running a high detergent oil additive prior to the next oil change won't hurt anything and might clear up some lower pressure oil outlets.
There are fuel additives for injector cleaning.
While the additive might quiet the injector tick, if it comes back I would plan on swapping out the injectors with rebuilt ones, i.e. you pay a core charge for rebuilt injectors you send back your old injectors and get the core charge back, less downtime than having your injectors rebuilt.
