Your pictures are small and difficult to see. If your implant seems to be exposed in the armpit area, it is possible that an incorrect size was chosen. With pectoral implants it is crucial that the dimensions fit you well.
Thanks for your question. The solid silicone implant is not has hard as bone, nor as soft as gel implants. Patients often say the implants feel like they are flexing their own muscle. Make sure you consult with a board certified plastic surgeon. Good luck