I am on Zyvox right now and I have not experienced anything like that. At least, not to my knowledge. I also have another medical problem that causes joint pain anyway...but it doesnt seem to get worse with Zyvox. The biggest problem I have had is headache, stomach problems, nausea, lowered appetite, on and off dizziness. You might want to call and talk to your doctor about this, specially since it last so long. you know, just to be on the safe side.