Yes, pain does occur in the joints, but there is no swelling or rise in the RA factor in the blood. So it does mimic RA in that way.
The reason it affects the joints is because the tendons and facia (the thin membrane that covers the muscles, like that icky stuff on chicken) that attach the muscles to the bones tighten up or thicken up and make it hard to move. This is why you have pain in the joints and in other places you wouldn't think FM would affect.
I hope all that makes sense.

I have had fibro since 1984 whoch started in my face, head, neck, etc. from a dental procedure (trauma) After 5 yers of Trigger P. Inf. it went into semi remission where I no longer needed weekly injections and was actually pain free for weeks a time. Of course- any trauma (car accident) etx. woud trigger it off. then I got an epidual in 2003 and it trigggered off RSD and FM in my entire back. I can just abouty walk.
Now, in sept. I was on my feet all day and they were burning but I just ignored them . Thought it would go away. I was having a party for a friend so I had to be "sociable". I am now suffering for it. I have terrible pain in the soles of my feet, ankles, legs and knees. I spend many days in bed. I take no pain meds as non(35) haave worked so far. I barely make it from day to day. I also have RSD in rt. arm from and IV.
I am now putting lidoderm patches on my feet and that helps the burning a bit and also is a nice cushion. You might want to try that.
This is a cruel disease with little treatment options.(for me- anyway). The only thing tht helps are TPI's sometimes. (only in upper body.--face, head, neck, shoulders, back)
Good luck
Sydney

I've talked to scores of people with FMS, and one thing that seems certain is that the symptoms can vary considerably from person to person. Some complain of severe joint pain. I myself have soreness only in the muscles and occasionally the ligaments. The most important factor in determining FMS are the trigger points. If you have those, chances are very great that you have FMS.

Several times I have run into situations with doctors where they will describe you as having fibro-like symptoms, but deny that you have the illness itself. It seems quite of few of them think of FMS symptoms as just a type of rection that can occur from various illnesses, like fever or nausea does. These docs don't seem to believe that fibro exists as a primary illness.

I hope you manage to get your symptoms under control, Trix!