biting pain after tooth extraction

Hi - I had a root canal on #15 (rear upper left) 4 months ago. since then, that tooth was painful to bite on. xrays showed no problem. Last week, an oral surgeon extracted the tooth (may have had a vertical crack) and put me on penicillin VK as the tooth was infected. It was a simple extraction, couple good yanks and it was out.

Now, 5 days later, I have an ache and biting pain with all the other teeth on the upper left. They were not sensitive to biting before the extraction. There is also coming-and-going pressure up the left cheek/nose. I am prone to sinus infections. I can't believe that all the other teeth somehow became fractured. Oral surgeon checked the site this AM and said it was healing, clot it still there though a little oozy.

Question:  could a sinus infection be the cause of the biting pain? Or is the PDL just irritated from the extraction?

Thanks-