My DS is fabulous - very tactile, loves holding your hand, jumping on you, holding your legs, being very physical. But if you ask him to come and give you a kiss, the chances he will are small. The only time he will, without fail, is if he's been carried and will lean across and give you one!
But should it concern me? I'm not even sure I classify him as unaffectionate, just not a big kisser and not yet learned how to hug...
does your ds kiss and hug at this age?