What can be done if my breast implant keeps flipping from front to back? (Photos)

I am sorry to hear about the problem you are experiencing. You demonstrate your concerns nicely. Although some “falling to these sides” of breast implants is quite normal when you lie down, if this occurs “excessively”, it may be a concern to patients.  This phenomenon is called lateral displacement of the breast implant;  it may be of concern from the visual and the discomfort standpoints (soreness or pain is certainly consistent with a breast implant displacement problem). Surgical correction is an option.
Generally, the lateral breast implant displacement can be corrected using an internal suture technique, decreasing the size of the pockets and moving the implants toward the midline.    In my practice, I use a 2 layered suture technique (capsulorraphy) to close off the space laterally (towards the axilla). The use of acellular dermal matrix is an option (although not usually necessary) especially if significant implant rippling/palpability is present.
 There are several important "factors" involved in this type of revisionary breast surgery. Most important (in my opinion): plastic surgeon experience level.     In other words, experience level and technical expertise play the biggest role when it comes to successful  outcomes with this type of revisionary breast surgery.   Careful attention to postoperative activity limitations as well as use of appropriate postoperative support of dressing/garments are also important.
 
 I hope this helps. 
 

All smooth implants can potentially flip. However, your pocket can be tightened to make less room for the implant to flip. If your implants are behind the muscle and they flip with flexing, your implants could be moved to sit in front of the muscle. You might even consider going smaller if you have pain when the implants shift.

This is not common but I believe it is more likely with higher profile implants especially under the muscle. Options include tightening the pocket to prevent the lateral displacement and help prevent the implant flipping, switching to smaller implants, and if the muscle is significantly moving the implants then you may need to change the plane and put them in front.