There's really nothing you can do. I had my emg done on both sides of my body from lower back to ankles. I felt sore for the next 2-3 days but the test itself while not exactly pleasant wasn't horrible either. It upped my pain a bit too but I think it's only because he did it over so much of me! lol
Over the past 6 years and studying I've done, I seen that people who have higher touch sensitivity tend to find an emg very painful. The ones who don't have it that bad or have no touch sensitivity at all, it wasn't so bad. At the time I had mine done, I only had sensitivity to air and not touch at all.
The emg of course won't provide any info to do with rsd, but it's common to have one done because it is very helpful for a doc to know if there's nerve damage or not involved in the limb that has rsd in it.
I hope it's a good test and I'll be waiting to hear how it went on Monday.
Hugs,
Karen