So the last two classes I've rolled at, I've felt this very strange burning sensation in my arms when resisting armbars and when my arm is extended for an armbar. I feel it primarily in my elbow, right where it bends. I've been armbarred plenty of times, so this isn't the pain that is usually related to being armbarred. It's also not the sort of pain/exhaustion feeling you get after you lift weights. It only happens when I'm being straight armbarred. Kimura/Americanas are fine. My arms feel perfectly okay a few seconds after the armbar is released. What the hell is going on?