It's still the 6th vital sign.
If a patient is in pain, their HR, RR, and BP can be affected. If you solve the pain issue, you'll get a better picture of what the patient is really going through.
I follow my assessment and doctor's orders. Does it mean overmedication? Not necessarily. If I gave the patient their PRN and they don't exhibit any adverse effect, does it mean I overmedicate them?
Bottomline, nurses are there to assess and evaluate, to relay to the doctor that the treatment is too little or too much. How can it be then that a doctor can overmedicate when it is still nurses who administer the medication?