K.P.
My son is getting over his cold, and I gave him warm broth in his sippy's along with Chamomile tea, and he really liked that. Try warming him up from the inside.
Along with what Red said (I'm actually going to get what she suggested, thanks girl) and try that too, but the same brand has a baby chest rub and it has really worked for mine too. It makes him sleep better.
Also elevated his crib mattress. Put a pillow under his mattress to lift it up a bit.
Hope he feels better soon! Lots of cuddles from Mom should help too!