When I told my best friends about my personal pain scale, it really helped me function in social situations. People who know me well are always able to tell when I am in pain, but the best thing is if people can tell a little before it hurts too much, without us having to actually talk about it.
It's so much easier hanging out with people who can just ask, "Where are you at?" and I'll say "5" and they know that means we ought to be heading home soon. That way I don't have to even think about the pain, or try to convey that it hurts so much that I may need to lie down soon.
As a chronic pain patient you don't want to nag, complain or focus on your pain in any way at all. It's a matter of life, you deal with it.
Sometime I want to design my own T-shirt with a meter gauge on it, and I can just adjust the arrow to my pain level. Non verbal communication, I love it:)