Sore Nipples Pumping

Hello, i’m 4 weeks pp and have been exclusively pumping since week 2. I have been experiencing sore nipples after pumping (sore to the touch) and it is also slightly pinkish. Would like to ask if it is normal, or is it a symptom of mastitis? There are hard lumps present when i am engorged but all lumps disappear after pumping. But my breasts will also quickly feel very full and heavy, probably within the next hour. Is it normal too? Thanks! #FTM