Funny this came up.
Mine started making the same noise 3 weeks ago towing thru PA on my way back to Ohio. Same thing, right side of motor, louder when passing or by walls, ect.
My truck had 29,500 when this started, and I was literally days out of warentee. Took it to the dealer, they checked it out and gave me some BS about my oil filter being to small, causing the oil to slow down around the lifters causing a ticking, there is even a TSB they printed out about it. I don't believe that crap for a second though. So now I am 3 weeks out of my 3/36, but I am bringing it back there this week anyways and it there is something wrong, they WILL fix it because it seems like this is a common problem.
Hell Ill fight them if I have to, get lemon law on it or something.