Your description does indeed sound as if you may have suffered "traumatic capsulotomy" and may require surgical repair of the ruptured capsule.
Every patient with breast implants has a scar (capsule) that forms around her implants. If it is soft, thin, pliable, and larger than the implant itself, there is softness and natural movement and "feel" of the breasts. If the scar capsule is thick, tight, or unyielding, the breast(s) can feel hard. In no case does the implant ever get hard. And with the most recent generation of cohesive silicone gel implants, a blow, injury, or trauma to the chest could be so severe that the implant might "rupture" by breaking into two or more pieces (like servings of Jello), but present implants cannot "leak." It's interesting that you aren't concerned about implant rupture, as this is most patients' concern whenever they have had a trauma to the breast area--though the implants are almost universally fine, and the damage is to the capsule, as you have correctly surmised.
Older silicone implants (15 years or so older than present) were not cohesive, and could leak if punctured or ruptured. Capsular contracture (CC) back then was much more common, and was often treated by squeezing the capsular-contracted breast from the outside (closed capsulotomy), which was designed to intentionally rupture the capsule, enlarging it so that softness would be restored. However, this often damaged these old implants, or caused the capsular tissues to bleed, inducing recurrent and often worse capsular contracture. Plastic surgeons have abandoned closed capsulotomy because of these problems, but also because we are much more knowledgeable about the causes of capsular contracture (predominantly surgical bleeding or bacterial contamination causing biofilm), and are able to avoid CC by careful and precise surgery and bacteria-reducing steps such as Betadine or Adams formula antibiotic irrigation and use of no-touch technique via the Keller Funnel. Better implants, better surgery, better results, fewer capsular contractures!
But back to your "wondering . . . if the scar tissue pocket has ruptured." It certainly sounds as if this might have occurred, with the breast feeling so much different compared to the opposite side. I wonder what might have been so vigorous a force or trauma to your breast capsule that could cause this. The force to rupture a fully-healed (surgery 1 year ago) capsule (even a thin, soft one) is not insignificant, and this didn't just happen during your sleep without your awareness. You didn't just "wake up" with the pain and distortion you describe.
Something major happened; please be honest with your surgeon since this is something that is not the fault of the surgeon, the operation you received, or "sleeping on your belly."
I raise this because I am concerned that you need to be OK and in a safe environment and that you don't have other injuries or concerns.
Yes, you will need additional plastic surgery, but please ensure that you are not in a situation where this severity of trauma to your breast might happen again! Best wishes! Dr. Tholen