Hi, I just got a beautiful Jazz bass yesterday (MIM Standard, I liked it better than the American I tried anyway!) and I'm experiencing some pain in my left hand when I play, especially when I do something which involves my 3rd and 4th fingers and requires more pressure, like on the lower frets or on scales going across the whole fretboard. I think it has to do with having the strength to stretch for and fret the note and the muscles in those fingers corresponding with my thumb. It's in the lower left area on the palm where the thumb comes out of, moving to the upper right. I'm not sure whether I'm putting fingers at a weird angle or whether that muscle needs to strengthen and will do so with time. Actually, I've been experiencing something sort of similar when playing guitar (regular 6-string), which I do a lot more of. When I reach my pinky in a certain way the muscles between the thumb and the pinky get uncomfortable. Not really a sharp pain, but it just feels like something's not right. I would think that this is a problem in my thumb position but from descriptions and pictures I've seen of proper thumb placement on the back of the neck, I think I'm doing it right. And my fingers are arched over the fretboard, and not at any slant that I've observed. Has anyone experienced something similar? If this is merely a matter of building up the strength and stretch then that's fine. I've been playing a short-scale bass, and not very often, so I can see how this might be a bit of shock to my hand. But I don't want to damage myself if it's not. Many thanks for advice! By the way, I'm learning Rush's "YYZ" (I'm not even a big Rush fan, but I want to learn this) or at least parts of it for my first learning project on my new bass. And that main rock riff (when it busts out after the intro) is causing me the aforementioned pain, to give you an idea!