Breastfeeding 5 days old.

Lucy
I pump 2 bottles today, a 5oz! 
 is it normal for your breast to feel light after pumping?
 He's on breast on all day long I still get heart burn does it mean more milk coming in ! I just feel light but I'm still nursing him every 2-3 hours 
He's only 5 days old. Help? 
&& how long after pumping first bottle to start pumping again? Is it every 2 hours or 3-4 hours