What Causes Swelling And Pain In Joints While On Azithromycin?

I was on Remicade & my Dr discontinued it due to me having bacterial pnemonia. he prescribed azthrimicin 14 days &Flagyl 10 days within 12 hours of taking these meds I developed all over joint pain and swelling which has been consistant even after completing the meds for 4 days now. I can hardly move around without taking the edge off with aspirin. I have no allergies, am 5'2" 128 lbs.