Pain in back of both legs after Breats Augmentation: Could it be a blood clot?

Please see your surgeon as soon as possible. This could be a sign of a blood clot (deep vein thrombosis). Best of luck.

If you are worried about blood clots in your legs, it makes sense to have a duplex study to be certain whether you do. There is no harm in checking for this issue.

Pain in the legs especially the calves just after surgery in my mind is a deep vein thrombosis until proven otherwise. You should immediately discuss this with your surgeon and figure out a plan with him.  

Although this is a possibility it is unlikely given the nature of this procedure.  The easiest way to sort this out is to have an ultrasound as has been mentioned.

Although uncommon, it can happen. The standard evaluation for this would be a doppler study of the leg veins, and this can be done at any vascular lab, though it must be ordered by a physician and scheduled. I would not write the symptoms off to positioning in the OR.All the best.