If implants are under muscle, why can I feel the bottom of it through my skin?

Because of the anatomy of the pectoral muscle, it only covers the upper and central part of an implant, not the outside or bottom area. It is normal to feel the implant on the lower and lateral parts of the breast. The form-stable shaped implants that you have should stay in place very well.

the lower pole of the breasts does not have muscle cover over the implants since the pectoralis muscle only covers the upper and the front part of the implants, not the lower border. Since that tissue is thinner implants are often more palpable. 

Many implants are palpable in the lower pole because there is less soft tissue coverage.  Best of luck.

Hi - this is quite normal.  The pectoralis muscle only ever covers the top portion of an implant due to it's anatomy & shape.  If you are concerned, then get your surgeon to examine you.  Take care

Yes, what you are describing is commonly encountered after breast augmentation surgery. This palpability of the breast implant occurs in areas where muscle or soft tissue coverage is not present (lower and lateral aspects of the breasts). You will find much more information regarding dual plane (sub muscular) breast augmentation on this website as well. Best wishes. 

It is quite common to be able to feel the implants, especially gummy bear-type, at the bottom of the breasts.  Most surgeons who place them under the muscle divide the bottom portion of the muscle so the shape of the breasts will be more natural, and this allows the bottom part of the breast implant to "peak out" from under the muscle, and if you are relatively thin, then you can feel the implant there.  Not sure what you mean by sagginess.  Pictures would help.

What you are describing is normal even with the use of sub muscular technique and gummy bear implants.  As long as there is no visible rippling, I see no problem.Good luck and take care.