I'm not really sure...but you should call your doc to find out. My undertanding is that our bodies go through lots of changes during pregnancy...some things that we would never imagine would happen. but check it out with your doc.
the tip top of my tum (directly under my boobs) gets hot all the sudden, the DR said it's probably stretching causing it to feel hot sensations I'm 32.5wks & have done this for about 5wks or so :) So I'm sure it may be the same thing for u, just u feel cold instead of hot, mine doesn't hurt just very akward :) Since u r itching (when skin stretches it tends to itch) I bet ur just making room :) LOL