Sinus pressure with no congestion

I’ve been having what feels like sinus pressure for the last few months off and on. The pressure seems to be right in between my eyes and sometimes it feels like it’s behind my eyes but no congestion. I’ve used nasal rinse. I have taken allergy pills but nothing seems to help. Went to the ENT to check my sinuses and they said they are clear. Not sure what else it could be when anyone else have the same issues?