After my FUE hair transplantation last week, I have pain in my right leg foot, could there be a connection?

Foot or leg pain and hair transplant surgery is not likely related unless you have a blood clot from sitting for a long period.  Blood clots can be a life threatening condition so contact your doctor ASAP.

Leg or foot pain after a hair transplant is probably nothing to be alarmed about.  Having said that, prolonged  static positioning can cause tissue injury, nerve compression, or promote the formation of clots in the lower extremity. While rare, it's not impossible to develop a clot, particularly if one is prone to clot formation.  To be safe, see your doc.  It is always better to be over-cautious!

Maybe during the FUE you were positioning yourself in such a way that pressure was exerted on one of the nerves to your leg. Check with your surgeon