I think, it happens a bit differently for everyone, Alisha.

For me, It started in my left arm and between my shoulder blades, and up (Thoracic Outlet Syndrome). Then, it crossed over (after a few years) to my right upper quadrant.
Then, after a couple more years, it went to my left leg, and quickly to my right, and then it was full body.

So, No, it doesn't happen 'suddenly', but sometimes may surprise you. So, I'd go with the small pains, and then one day you'll realize that it's invading elsewhere. Others will chime in with their experience, I'm sure. I've had this for 28 years, and I sorrily believe that if you have it, it's already in your body.

I'm sorry to say, that it's possible that it will spread, since rsd is really quite like a short circuit in our sympathetic nervous system. Short circuits do spread.
But don't concentrate on that!!

Concentrate on What you CAN do!! And, all the blessings you have.
It can always be worse!

Exercise, eat right, and get good pain relief, from a knowledgable doctor. It's a circle, without proper pain relief, you can't exercise!
I was taught early on that it's a 'Use it or lose it' type of disease.
I agree with that.

Hope you're well!

Pete


asb