What Causes Breast Pain?

hello,my mother is having left breast pain of the whole nippel area also with foul smelling discharge,not sure of the color of fluid....its being going on for about a week my mother is 52yrs old..no breast cancer history in family or in her...she didnt have any known trauma to breast area...its swollen,red feels warm like when u r breastfeeding,my mother isnt lactating suffers from gastrointestinal prblms..but nothing major takes highblood pressure medicine. also recently ger g.i.doct.gave her an anti-flam.for her stomach....that her general info also has had strange neck left side pain.with headache...in general what do u think can be her priog.thanks for ur help?????so worried....................