Millymoo, I am wondering why you ask advice on 3 patients.
I advice you to look into the background of dynamic hipscrew. You might find out that there might lie a clue or 2 why this person is in pain (apart from potentially having a low pain threshold).
The idea of a dynamic hipscrew is that it will allow the 2 parts of neck of femur to come as close together as possible to allow the best chance of union. If there is a resent X-ray you could have a look if that happens. Look into complications of dynamic hipscrew. It is a good method but e.g. screws which should keep t in place might not have enough hold (e.g. Osteoporosis) or the fracture lines do not match, or the patient had another fall not registered which has damaged the dynamic hipscrew.
Anyhow pain is in general normal as long as it decreases over time. the 1st couple of days- week is expected to be rather painful but over time it should settle. let the patient give a number to the pain experienced. (10 is the most intolerable pain someone can experience, but in general when a patient gives it a 10 a psychological influence is expected to be part of the pain. To my idea a 10 in pain means you prefer to die or will pass out due to pain)