How long does it take for the muscle to stretch and accommodate the implant? What can I do to help stretch out the muscle?

Sounds like you had both a breast lift and a breast
augmentation on both sides. You may have needed more skin tightening on one side
than another which can make a difference in how you feel between the two breasts
postoperatively. Both of muscle and skin have to stretch to naturally to 
accommodate the implant. Much of this happens within 3 weeks but you should have
a good idea of what they will look like by three months. It is important to do
gentle range of motion exercises with your arms so you don't stiffen up. Follow
your surgeon's advice about possible massage. I often recommend a warm soft
washcloth on the breast at this point to soothe and soften.

Thanks for sharing your concerns with us.It takes approximately 2 months for the implant properly fits under the muscle. In my practice, after performing a breast augmentation i recommend to my patients to limit the movement of the arms for two weeks. After that, you can move your arms taking care and always with common sense. In this regard, it's not advisable to carry weight to prevent the implant out of position, and allow the formation of the physiological capsule around the implant, also to avoid pain and breast swelling.To talk about the last result of your surgery we need to wait at least 4 months. Kind regards,Dr. Emmanuel Mallol Cotes.-

It takes six months to a year for the implants to completely soften and seek their natural position. In the interim you can control the placement with smooth implants by using a superior band or /and tight bra. If you have smooth implants massage can help when your plastic surgeon suggests. Check with him and good luck...

Thank you for your inquiry and congratulations.To answer your question, every patient is different and every surgery is tailored to fit the very specific anatomy of the patient. With that perspective, you should be a little more patient give it some more time especially that you less than 3 weeks post-op.I recommend that you keep communicating with your surgeon and to follow his/her recommendations hence working as a team together.Best of luck to you!Ali Sajjadian, MD FACS

Most women have very differing breasts and it is common for plastic surgeon to have to do more surgery on one side when compared to the other. This is especially true with revision cases. Give your self some time. 4-6 weeks is when the muscle should accommodate most noticeably. A muscle relaxant may help in the interim. 

At 17 days you are very early in the post operative course for this procedure.  Hopefully the firmness you are feeling under the arm is not the implant.  The thicker part of the muscle is at the top.  IT is not uncommon for this muscle to go into spasm and form a bulge at the upper pole.  I usually have my patients stretch and move their arms back and forth to help the muscle relax.  Ask your plastic surgeon for specific advise.  

Breast implants used in cosmetic breast augmentation surgery are placed either under the muscle or on top of the muscle in the subglandular plane.  Initially after surgery the tissues are tense and swollen.  With rest, these tissues will begin to relax and stretch to accomodate the new volume placed in the form of breast implants. Early activity may cause more swelling of the tissues and may prolong the phase of accomodation of the tissues to the new volume.  Rest and avoidance of significant activity will hasten this process, but even in the best of circumstances, it often requires at least 6 weeks in most women.  Oveactivity will lengthen this time frame.  Early activity and early exercising will also lengthen the time of resolution of the swelling.  In most cases, the soft tissues of the chest wall will soften and relax allowing the implants to find their final positions.  This often requires 12 weeks to achieve their long term shape and appearance.The process is usually asymmetric, meaning that one breast usually progresses faster due to less activity of the associated arm and chest wall muscles. Generally speaking, the breast of the non-dominant hand (which is used less than the dominant hand), will soften faster than the dominant handed breast.  If you are concerned about the differences in your breasts, additional discussions with your surgeon may be helpful.