Im 19, suffer sever left breast pain with a large vain that goes through boob and branch vains to nipple i hve been referd to breast clinic what mean?

Probably: Nothing more than pain and in erased vascular urge from having large breasts. At your age I am glad they referred you to a breast clinic. Since they specialize only in breast issues if a reduction is needed, they would be the best for cosmesis.

Variety of issues: Women with larger breasts often times have visible large visible veins. This may or may not be the cause of your breast pain. However, at age 19 it is unlikely anything serious. They probably sent you to breast clinic to see if this is fibrocystic breast changes or mastodynia (breast pain).