TMI: My left boob is killing!!

I'm 20 weeks 2 days and my left boob is hurting! It doesn't feel sore just fills like someone is injecting it and it's gonna explode lol my boobs did grow tremendously from a size d to about a triple d maybe E and I know they are only gonna grow more I don't get this!! I started growing boobs when I was like 8 got my period at 10!! Lol wth is going on?!! And now my boobs just keep growing and growing when will they stop?!!! Ps I also have vains all over them looks creepy and my nipples are hazelnut colored.