I don't think that that grafting is the right answer for you. I think that more of your muscle has to be released. There are still fibers of your pectoralis muscle that are preventing your saline implant from sitting in the proper position. If the pocket in which the implant sits is not at least the size of the implant diameterthen part of the implant will get pushed and distorted.
An in person exam would be needed to make an actual recommendation. This looks like it may be a constriction in the capsule that has formed around the implant, and releasing the pocket might be best (a surgical procedure). Fat grafting may be a simpler option, but an actual exam to determine the problem is needed.
All the best.
Asymmetry after breast augmentation
Asymmetry after breast augmentation is inevitable and minor asymmetry should be expected. You have to remember that you are your own worst critic and that other people may not be able to recognize the same things you notice.
Overall, this is a minor issue but if correcting it would help you feel better, it may be worth it. This may be due to a preexisting asymmetry or it could be due to an asymmetry how the pocket formed around the implant. You could try releasing the pocket to see if that would correct the problem and would be a minor procedure.
Hopefully you can get the results you are after.