Mastitis
If bacteria collects as a result of sore nipples or if the milk becomes greatly clogged for a sustained period, mastitis (inflammation of the breast) may result. This leads to headache and pain in the limbs as well as low-grade fever.
If the condition progresses, the inflamed breast becomes hot, very painful and high-grade fever develops.
Mastitis is a condition which must be taken seriously, so visit your doctor without delay!