Are Leaking Left Implant and Sore Ribs Linked?

I wouldn't worryabout a possible leak of your saline implant.  Even if you have a saline leak, it is not harmful to you or your child.  In reality, the pressure from your increased breast size and abdomen is probably applying more pressure than pre- pregnancy.  I would wait and see how things feel after you have given birth and finished breastfeeding ( if planned).  At that point, if you are still sore, then I would check with your surgeon.

As much as an implant pushes your breast and skin outward to create a larger breast, your breast and skin push back on the implant. Over time, this causes a remodeling of the ribs of the chest wall. This happens with any implant and we commonly observe this phenomenon with chin implants. During pregnancy the engorgement of the breast tissue can exert force downward on the implant causing greater remodeling of the ribs. This varies among individuals.

Being pregnant in and of itself, can cause discomfort and soreness in the ribs from the weight and stretching. I doubt it is from a leaking implant.