Yes, it will get better. Your milk must have only JUST come in! It won't take long.
Cabbage leaves can help with mastitis pain I think.
Make sure you feed as much as bub wants. That will help regulate the milk your breasts make.
If you get any red, hard or burning sore spots, make sure bub feeds off that breast. Mastitis comes on quickly. I have never been as sick as when I had it. Best to try and avoid it. If you don't have much info about it, google it so you are aware of what to look out for.
My boobs were like massive watermelons 3 days after birth, but settled down quite quickly.