I have about a 7" long plate and a handful of screws in my forearm -- along the pinky side of the larger bone.   Had surgery to shorten my ulna because it was too long in relation to my radius causing pain, reduced range of motion, and cartilage damage in my right wrist.   Basically, my wrist is worn out and there is no fix for that. So the surgeon cut 4mm out of the bone, pinned it back up, and had me in a cast for 2 months in hopes of gaining me some increased use of that arm/hand.  Had the surgery 2 years ago.  Hardware hurts every day.   Weather changes are particularly bad, as is being in the cold for an extended time.  I feel the screw heads directly under the scar.  Have bumped against them hard enough to start to split the scar open and it bleeds.  Not fun.  Also seems like I feel the hardware when pulling on wrenches hard like the bone wants to flex a little and the metal doesn't.  I can't afford the cost or the downtime of another surgery, so I'm going to have to live with it. 

If it is a viable option, I'd recommend your wife get it removed as soon as the surgeon will do it.  She's 21.  Life only gets busier and more stressful and the body only gets more and more worn out. Chronic pain wears on a person.  Doing it sooner rather than later would seem to better for her.