Stiff & painfull hands & wrists in 29yr woman please read on--->?

My wife is 29yrs old & had our baby 5 months ago since then she has had a very sensitive wrist, Over the last few days both her wrists, hands & elbows have become very stiff & painfull. Has anyone got any experience of this problem or any tips on what we could do to ease the pain?? she is also feeding our baby could this have anything to do with it?