In my experience, breast implants tend to help “camouflage” the concavity, making the cleavage area look deeper. Often times postoperatively is hard to know that the patient initially presented with pectus excavatum. I usually recommend under the muscle for longer term results as well as reduction in potential for rippling and palpability of the breast implants. Each patient is different so it will be best to have an examination. Often, patients with pectus excavatum have medially sloped chest walls ( sloped towards the cleavage area); care must be taken during the breast implant pocket dissection to avoid the implants coming together too close in the sternal area. Also, patients with pectus excavatum may have their nipple/areola complexes relatively medially positioned on their breasts; without intervention this inward leaning appearance of the nipple/areola does not improve with breast augmentation surgery. I would suggest that you meet with well experienced board-certified plastic surgeons; asked to see lots of examples of his/her work. Best wishes.