Do I have signs of symmastia?

I am sorry to hear about your concerns after breast augmentation surgery. I understand your concerns; your breast implants appear to be very close to one another in the midline area.  However, they do not cross the midline and therefore you do not have "true" symmastia.  Revisionary breast surgery (capsulorrhaphy) may be necessary to improve your breast implant position. You may find this attached link (demonstrating similar cases) helpful as you learn more. Best Wishes.

#Symmastia is a condition which can occur when the implants are too close together. Patients often refer to this as a “uniboob.” Occasionally, the space or pocket for the breast implant is created towards the center, or the tissue stretches, forcing  the implants to fall too much towards the center of the breasts.  Correction of this problem may involve using different implants such as textured, a smaller size, or a smaller base and placing the implants in a new pocket. Sometimes, this may require surgery in more than one stage to allow the tissues to heal and then place the implants. If the implants have been placed above the muscle, converting them under the muscle frequently will help and, again, the use of a dermal substitute may be required for additional support if the tissues are thin. The techniques of #capsulorrhaphy and #neopectoral pockets may apply here as well. You show signs that may be symmastia. However, it is best to consult with your Plastic Surgeon to better determine with an in-person exam. 

I do see this as a problem but it is not symmastia yet.  If the implants are truly under the muscle this would not occur unless the muscle was cut medial.  This is something which is not commonly done.   Revision surgery may be required. Good luck