Thanks for the query.
Pain in the breast and nipples just before periods can be seen in perimenstrual phase.
But as you are having continuous pain try to rule out any possibility of infection.
You can go for weaning now, as you son can adapt to top feeds at this stage.
You can take some analgesic
and anti-inflammatory tablets to decrease the severity of symptoms.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429