Going through gorgstation sucks. It looks like I had breasts enlargements and how they hurt and are heavy. I wonder how many pounds I am carrying on my chest? I would guess ten.
Mine grew quite a bit when my milk came in, too.
You plan to nurse the baby, right? Is he nursing OK? Do you have a breast pump? It will help a lot if either the baby or you empty your breasts as much as possible each time you nurse. Did you get some Lansinoh or PureLan at the hospital? If so, then use it on your nipples, it helps keep them from getting dry and cracked. I think you can also get it at Walgreen's if you have one there. I didn't use mine enough in the beginning and my nipples cracked, which was awful.
If you get a very sore lump in your breast, that could be a plugged milk duct or maybe the beginning of mastitis and you would need to see a doctor and possibly get antibiotics for that.