Inverted Nipples

Urwa • I have awesome family❤️
Hiiii
I am a mother of one baby girl
My baby is 11 months old and since her birth I have breast feeded her normally
But recently like almost a month ago my nipples started to invert and go inside my boob
I have seen my doctor and he said that they are totally fine and nothing's wrong but he can't figure out why they are inverted
I have been using breast pump because my child can not hold onto them 
And the pump hurts bad
Some of my friends suggested me to get nipples pierced 
What do you guys have to say about this??