Welcome to health care magic.
1.As you are saying painful large
lump in the breast in your age - i would think in terms of
breast abscess.
2.Sorry - but you need medical attention. An
ultrasound scan will be ideal to start with.
3.An ultrasound breast will help to know about the nature of the lump its source and where are its extending.
4.If the lesion / lump is small and cystic / abscess usually monitored, but since its big and symptomatic , a small
incision and drainage followed by a course of antibiotic treatment might help.
5.It could be inflammation in breast and glandular breast feeling like lump - in that case just a treatment.
6.So please make your way to your Doctor and get needful things done. Good luck.
Hope i have answered your query.
Any thing to ask do not hesitate. Thank you.