welcome to HCM,
The pain after Tdap usually does not stay for more than 3-5 days. it is possible that while giving shot, nerve has been hit and agitated by needle. It may take several weeks for the pain to disappear.
Another reason for persistent pain could be infection either local or in blood. bacteria or virus may enter into blood stream. it can cause severe pain
i n whole arm.
i would suggest that you should go the Doctor to rule out any systemic infection or local Injection Abscess
. If there is no infection, then considering nerve pain
, you may be advised to take tab Neurobion
for 1-3 months.