A gap between the breasts is normal, but some women are wider than others. You did not post a nude photo, so I cannot be specific. You might have some excess skin which can be removed with a lift. I would suggest meeting with a board certified plastic surgeon and discussing your concerns.
It is certainly possible to get a more full upper pole by utilizing breast implants. The type, style, and size of implant would need to be chosen based on what is called tissue based planning. This technique requires choosing the correct implant based on your chest wall "base width" amongst...
Even if you have a significant amount of your own breast tissue, implants will tend to profile shape throughout a variety of different positions, including lying flat. Most silicone implants are made of a thick (form stable) gel. This cohesiveness is what provides stability throughout movements...