Help engorged

Elizabeth • BFP on 4/10/17 for baby #2 ❤️ [Baby #1 = Jan 2016]
I have a 4 day old that's an eating champ. My breasts are SO ENGORGED and I'm in pain. I pump for 10 mins after feelings bc it's so painful. Any tips/ideas to help? Also, my left Armpit has a burning sensation... Is that normal? What should j do? I'm a ftm!