Here’s a new problem: I’ve been following the first book and dipping in and out of other things as well. I recently joined bass guitar Pro lab. It’s a good resource for new to intermediate folk but I’ve run into an issue. When following a course on there using the third finger box shape I’m finding that I get pain in my fretting hand at the big muscle at the base of my thumb. Is this simply because I’m not used to using it after following the Hal Leonard method? Anyone else get this pain when moving on to one finger per fret? This is worst when I’m using mainly first and third fingers.