Breast unequal in size no lumps?

I am 21 yrs old virgin. My left is noticably bigger than right n specially when I bend. My pain (both) before starting period and goes off after it n becomes lumpy. But left one is too big and touches my hands n experience sudden pain in chest (left ) when I sit for long. Getting married soon. Just not able to tell my mom... plz advice. I could experience lumps before but they r gone now .. what to do ??