Can Naproxen increase swelling?

My doctor prescribed naproxen after he diagnosed me with coccydinia (inflammation of the coccyx) to reduce swelling. I have been taking it for 5 days now, and just yesterday the pain in my coccyx spread to my lower back as well and my coccyx became more swollen and my back began to swell up. I don't know what could have caused that except the naproxen, because I haven't done anything to strain my back and in all the time I have been experiencing coccyx pain (over a a year now), the swelling has never spread to my lower back. I know I'm not allergic to naproxen because I have taken it in the past with no incident.