First of all,I don’t think that the lump in your breast is a serious one,since it’s there for so long.It could be a Fibroadenoma or a cyst,( Both benign )but please be aware that all breasts lumps should be evaluated as soon as they are noticed.
Nipple discharge usually occurs when nipples are squeezed and the solution is not to stimulate them so the fluid stops.Also every woman is different and no two women's breast will look exactly the same even when fully developed.
I would suggest to make an appointment to see your Doctor about the lump in your breast.He/she might order an Ultrasound to make sure about the nature of the lump.You know,delaying a breast exam will only add more anxiety and prolong your fear.
So please make that phone call okay?
All the best…