7 week old kitten making noises at litter box what's wrong?

Whenever he goes to the litter box he meows and meows. Any advice of what could be the issue or is just kittens being kittens?

At 7 weeks, many kittens are still quite new to moving their bowels without help from mama.  It is really common for them to do exactly what your kitten is doing.  As long as he gets around to doing his businesss eventually, there is no problem, and he will outgrow the meowing.  I'm not sure if that's what they do as infants to encourage mama cat to lick his bottom and stimulate him to go, but I suspect that's the case and it's a leftover baby behavior.  Since even adult cats tend to meow in distress a little before vomiting, I suspect that goes along with any kind of tummy discomfort.