RSI in my middle finger

Okay, this sounds like an April Fool's Joke, but it isn't: in the past week or so, the middle knuckle of my middle finger has started hurting. A moment ago, I justĀ flickedĀ the scroll bar on my mouse and had a serious shooting pain as my finger "tented": I think I have a repetitive stress injury! Amazing -- typing is such a major part of my life that I have finger strength like a rock climber and I've never had the slightest indication of carpal tunnel syndrome. To have my wickedness felled by a mouse wheel -- What a world! What a world!