That explanation helps a lot.

I can't give you medical advice, but from experience this sounds like you may have pain from the nerves healing or regenerating. Nerves become VERY angry when disturbed or cut during surgery (both normal occurrences.) They can take a very long time to regenerate - after one hip surgery, I had intermittent pain for several months along the outside of my leg, and still have a numb area 10 years later.
Or there may be a problem with the stem and bone growing together. There is a coating on the stem that the bone should eventually link with, and every body responds differently.
In your situation, I would try asking one more time for help from the surgeon, then go back to my primary for assistance finding the right doc.

Have you tried ice, heat or gentle massage when the pain happens? Can you pinpoint exactly when it happens?

Sue