I've been playing a little over 2 months now. When doing fret hand exercises low on the fretboard, I still get some cramping/discomfort in my palm right under my thumb. It is from applying a lot of pressure to the back of the neck. I know you are supposed to keep your thumb relaxed but I can't make the stretches lower on the fretboard without applying pressure. When does this get easier? I do stretching/fret hand exercises daily but it seems to be coming along at a snails pace.