I've noticed that I very frequently tense up while I'm playing, mostly in my picking hand, forearm and shoulder. I do it with my left hand too, but not as bad and for some reason I seem to have an easier time correcting that if I concentrate, even while playing full speed.
Can you guys recommend any good drills to help with this? I've found plenty that basically involve slowing waaaaaaay the hell down while playing relatively simple stuff and focusing on staying relaxed, but I don't really have a problem doing it at slow speeds or moderate speeds. I'll practice it slow to a metronome and gradually speed up, but I eventually hit a speed where I can't focus on playing stuff right AND staying relaxed, even if I can do it consistently at 5 or 10 bpm slower.
You'll probably get more specific advice if you post a clip of how you're currently doing it. What technique does it happen with?