What causes sore nipples for weeks?
Puberty can make nipples ache in female humans and some
Pregnancy can also cause nipples to feel pressure like
clothespins for long periods of time.
There may also be a disease that has caused this. If the
condition continues without cause like puberty or pregnancy, it may
be cancer and should be checked by a doctor.
The only other option is if you had some sort of physical
accident and hurt your nipple badly. Breast-feeding children may be
enough to harm sensitive people.