What a great thread! I'm so glad you bring this up because I'm pretty sure we all deal with this to some extent. It IS frustrating.
Most people have no idea what an SCS is and it seems futile to try to explain it to certain people. Number one, they don't comprehend what our pain condition is all about, let alone this strange device.
I like what Yellow has to say and I can sure relate to the 'pessimistic' thing.
I go to a faith-filled evangelical church and several people are of the mind of "Why are you confessing you have PAIN!...you should be confessing you are HEALED!" I understand what they are saying but this pain is REAL and it affects my life tremendously and I need to face it, not deny it. yes?
So, when people ask me about my pain, I usually just say that I am trusting God to heal me, but for now this is how I'm feeling....

I usually tell people that the pain is still here, it's just that the SCS 'covers over' the pain, not take it away. Also I mention that some days are better than others and that I do get breakthru pain and flares, etc.
Like what you mention, Eliza, regarding the arthritis and other pain issues...perhaps try to explain that the SCS is for 'such and such' pain (in my case lower extremeties), but there are other types of pain involved as well, in which the SCS isn't able to address. If they are open to comprehending what you are saying, then great. But if it seems to go way over their head, then I just realize that no matter what, they aren't going to understand, so I keep it simple and leave it at that.

Anyway, this is a great discussion and I'm glad to be able to talk about it.
I'm so grateful for this place that we can all come together and understand each other. It's just nice knowing that there ARE people who really 'get it'.

I do understand the situation you are in, where people look up to you as a prayer warrior. You don't want to cast 'doubt' on things, yet this pain you feel is very very real.

Rae