Breasts change in volume, firmness, and the amount of loose skin over the years. It sounds likely that your right breast has what we call rippling, or visibility of the implant shell through the skin. This is common with older saline implants in patients with thin tissues, especially if the implants are on top of the muscle.
If you would like to have revision surgery, consider a silicone implant, especially one with a highly cohesive gel (like Natrelle's Inspira implant) to minimize the chance of rippling. You may or may not also desire a lift to tighten the tissue around the implant. Overall, I recommend seeing one or more board certified plastic surgeons to get an opinion. There is not really a need for surgery in your situation unless you want to improve the appearance.