is it worth stressing over

So 2 years ago I found a lump In right breast. It's also in my left breast
So recently I went to the doctors she examined me and could feel the one in the right.
She said it's probably just a gland.
Nothing to worry about 
And she said "do you want to be referred"? Not " il refer you"
I'm 21 years old. My nans sister had breast cancer. 
But if it was a gland or even a cyst wouldn't it go away? 
It's small, oval shape doesn't move and hurts when I poke it. And my breasts hurt around af