2006 Dodge Ram tapping noise

what is this tapping noise in my 2500 5.7L hemi v8 mega/slt/larime cab truck?? just started happing after a oil change. I tried changing to a heavier oil (10-30) then i added a lucas engine treatment bottle....and the tapping is still there,however somewhat better,with lack of noise..... my oil light has never come on and all my gauges are working. when i drive or acelerate it sounds as if it goes away. after i drive for a period of time and then park and idel the tapping will return only not as pronounced. this is not a loud tapping however ENOUGH to cause me alarm with possible major engine repair. Thank you