When I play, I kind of press my thumb up against the neck, and when I go to higher strings I seem to either slip it down or rap it over the top. When I press it against the neck, usually after awhile it starts to hurt. I have tried to put my thumb in other places, but I always slip it back there subconsciously because it feels natural. It seems to make my hand hurt after awhile, plus sometimes it makes it flow less. I was wondering if anyone has a suggestion for where to put my thumb. Any help is appreciated, thanks.
u cant really say "put your thumb here, here, and here" because everyone is different. the reason that your thumb probably hurts is because you dont play guitar that often, it used to happen to me a lot when i started playing jazz chords. eventually your hand strength will increase and you will be fine.

also, keep in mind that guitar greats such as john fruciante and jimmy hendrix played with their thumbs. and why not? its another finger...why not use it? i do when i play stuff that i know i cant hit because my other fingers are somewhere else.
Yeah I have a problem like that too. When I play barre chords, I use my thumb to bar the low E string. I've tried to learn it the other way but I'm too lazy. And it feels more natural with my thumb.
Quote by JewMasatFlex
the reason that your thumb probably hurts is because you dont play guitar that often

I play at least an hour a day though. I have been for the past few months, and have been playing (on and off a little bit) for almost four years, and it just started happening recently. It hadn't affected me before a week or two ago. Thanks though.