
At first I didn't care for the order in which the pain / plain paper concept was formulated. But then I remember of some of my pains (which thankfully don't include headaches) and I realized how dead-on was your description.
I also like very much the alliteration in both stanzas' opening lines'.
Alcuin

Thanks for your comments. Even after thirty odd years of these, I haven't become accustomed to them.

Having context, having read a lot of your work, I immediately put this in the category of your (post) war poetry. I don't know if that's right or wrong. I do know that within that context I find added poignancy here.
"memory's plain paper." There's something wonderful about that, because the worst memories do seem to be forthright, "plain as the nose on yer face" and such though we could wish away that they weren't.
I get thrown off a bit in the last two lines; I'm not sure why.

As for the last two lines: The so-called 'pleasures of the flesh' are no longer in my life, but the relief when that pain subsides is incredible. And, yes, the headaches seem to be the result of exposure to dioxin from Agent Orange. (You are very perceptive.)