2 Small Lumps Below Each Nipple, Saline Implant Valve?

   Implant Valves can be palpable after Breast Augmentation, and your plastic surgeon could fairly readily determine if this is the case.

Yes, depending on the patient's body type and positioning of the breast implants, it is possible to feel the breast implant valves (saline implants).

 I think you will be best off visiting with your plastic surgeon,  who after direct examination,  will be able to confirm your suspicions ( and potentially save you from unnecessary imaging).  If any doubt, best to proceed with the imaging studies.

 Of course, your physicians are in the best position to advise and/or reassure you.

 Best wishes.

You don't mention your age, but this is important as well - it sounds like they are the valves because they are in the same place on both sides, but your plastic surgeon should be able to confirm this with a quick exam.