Personally I would take whatever painkillers they gave me (I’m sure you have) wait a few hours to see if it starts to get better. If it doesn’t, ER. And if you are really unsure and don’t really want to go to the ER you can try calling your dr’s office who did the surgery and ask if you should be concerned.
I personally call and ask my drs if I need to go to the ER or if I can wait until our next appointment bc I have such bad anxiety and about if I really to go or not. Most of the time they either schedule me a sooner appointment (or an urgent appointment) or they tell me to go to the ER.