Ticking noise on a 5.3L

I have a 2006 Chevy Silverado 5.3L with 188xxx
mile on it that developed a noise a few days ago
and it's more of a tapping on tin type "ticking" that
is coming from the back side of the engine and it
also seems to fade in and out randomly but it
doesn't go away fully and if I bring my rpms up, the
noise gets a little bit louder and the tick/ tap gets
faster as the ROMs go up and it seems louder if I
crawl underneath my truck. The tapping is their
when I start my truck and remains their once it is
warm and even if I'm driving at 20 or 30 or 40 for
example, but if I floor it, the noise goes away until I
come almost to a full stop again. I thought that my
flex plate was cracked and I had it checked out
and it wasn't and I replaced my starter thinking
mabey the bendicks in the starter where bad and
wasn't fully disengaging it from the flex plate but
nothing. Would anyone might have an idea what
would be going on based off of what I've tried to
explain?