What Causes White Discharge,sore Breasts And Chest Pain?

Hey, Im 14 and i have started my period a while ago about the start of june this year. they havnt been all the same they have all been diffrent, some lighter than others and later also some are dis coloured. i had missed one and at the start of last month i had a very small thin brown period for 2 days it wasnt normal, and not enough for a pad or pantiliner. Now i have started gettin sore breasts and chest pains also white sticky discharge. Help me?