Sinuses exposed after extraction off tooth i have doxycyclin but still in pain?

Sinuses: If you hold your nose shut and try to blow and the air comes through your mouth you have a sinus exposure. If it was just that the roots of the tooth were long and was up in sinus area without an exposure then that is different. The pain can be many things, but is usually healing or dry socket. You should see your dentist for an evaluation.

May need see surgeon: It is not unusual for sinus communication after an extraction. This normally heals uneventfully, but if not, then surgical correction may be needed. This is usually best handled by an oral surgeon.