I have had a sinus infection for 2 weeks now and I've been on avelox 400mg once a day and sudal sr. I will be finished with the antibiotics Saturday. Wednesday morning I woke up and the left side of the back of my head was slightly swollen and I had pain going down the back of my head. What could this be? I would also like to know what I can do for chronic sinus infections I have been getting them really bad for the past 2 years.