Do I Have Congenital Symmastia?

Looks like symmastia.  Breast augmentation will make it more pronounced.  Your breast are beautiful and symmetrical with good size.  If the symmastia is a great concern, the i would not have breast augmentation.

From your pictures, it does look like you have synmastia.  I agree that your best and easiest first-line option would be judicious liposuction in the area of your cleavage followed by prolonged compression to get the area to scar down nicely and create space between the breasts over your sternum.  After that, if you want a breast augmentation, you can probably safely attempt it, knowing that that area must not be disturbed during augmentation surgery.  If it is disturbed you could recreate the synmastia.

Good luck,

Dr. Shah