Engine tick

So, over the past few thousand miles my engine has developed this very audible tick and I would like to get some input as to what it could be before I get it looked at. The tick is audible at idle but is worst at start up and oddly enough gets louder at engine shuts down too. This could also give clues; I changed my oil and filter this evening and noticed something when I added the oil. Immediately after adding the oil the tick was gone. After about ten seconds the tick returned. I checked the level and added a bit, again, no tick for about ten seconds and it returned. My thoughts are it must be something not getting sufficient oil. Could something be dirty or an oil passage be blocked or something of that manner?

Oil is 5w20 Mobil 1 and the filter is a k&n hp1010.

Thanks in advance guys,
Nick