Dear friend, welcome and thanks for entrusting your query here at HCM!
I am Dr. Prasad Akole (Critical Care Expert- http://bit.ly/Dr-Prasad-Akole) and am glad to address to your query here.
It seems to be an inflammed area that is giving rise to pain.
A screw rubbing against is an uncommon possibility.
Infection or nerve irritation
are other possibilities.
It is impossible to tell from distance.
Do you have any fever? Is there any pus/ discharge in the operated area?
It is better to ask your surgeon about it.
You can take pain killers like acetaminophen
till then and some NSAID
I hope you are fully satisfied with the guidance I gave.
I would be glad to answer any further queries. Please ask for any clarifications before closing and rating this answer.
Thank you and Good luck!