How can I cure my persistent sinus pain (frontal & maxillary sinus and temple)?

I have had a dull pain in my left maxillary sinus for over a month now and slight throbbing in my left frontal sinus. I also have pressure behind my left eye and right temple which is causing mild pain.

I can get some relief from the pain by placing the palm of my hand on top of the maxillary sinus and over my eye and gently pressing on it. I also have to press my left temple to get relief. I am also feeling very lethargic and irritable.

These symptoms were brought on from a mild cold over a month ago. My doctor checked my nose and noticed mild swelling in the left maxillary sinus. He prescribed 7 days antibiotics and prednisolone 5mg (3 tabs 2 times per day). He also recommended I take a decongestant and use a saline wash 3 times per day. My condition did not improve over this period.

Last year around this time I had frontal sinus endoscopy surgery after MRI/CT scan showed I had a blockage which was causing an infection (see images attached). My symptoms are similar this year but not so severe.

I also have a mild tightness in the chest (no wheezing) which I believe is linked to the allergy/sinus symptoms. I had asthma as a child and the tightness feels similar to when I had dust/pollen allergy.

Is it possible I still have an infection or could these symptoms be linked to an allergy.

Thank you for your help.