Thank you for your query at DoctorSpring.com
If there is a tooth with a deep or large cavity in that area, then the pain is mostly teeth related.
Sinus related pain is also usually associated with an infected tooth
If you have a painkiller tablet such as Paracetamol or Advil, take it immediately and then i guess in the morning schedule your visit to the dentist.
You can watch for half an hour after you take the tablet, still if pain is,unbearable pls go immediately to the nearby dental emergency or hospital.
Feel free to discuss further,