@pappy7926, I have been on the 3 drugs and they didn't cause neck pain. And don't think there's anything like that in the drug literature.
You write "...She woke up about 12 days ago with a severe stiff neck and pain." That almost seems like a skeletal or spinal response to something ... like from sleeping on a mattress, or working on computer, or bad posture, etc. I've recently learned at the NTM conference that there is some connection between NTM (MAC is only one of 150+ types) and mild scoliosis in patients. If the pain continues, I'd recommend your wife see a spine doc -- they usually have physical therapists and perhaps a chiropractor on staff with them -- they could rule out spinal/skeletal issues and if appropriate refer her to a PT who would work with her on exercises to alleviate the pain and strengthen her neck & back. I've just gone thru this, over the past year, and it's amazing what can be done without medication.
Best wishes, let us know how she is going.
Paula