First of all thanks for all the replies. I didn't take any classes from a professional teacher, don't have the time or money at this point. As for the doing damage - I don't think that I'm doing any damage since it goes away if I stop or after a some playing - like after a warm-up (a very long warmup...). I also tend to play alot when I do, but the pain begins in the beginning and goes away after a while. I know that if I was causing damage it would manifest somehow in other situations as well - it doesn't. I'm not ignoring it, if something will feel "unusual" - I'll stop and see a doctor immediately. I'm keeping my attention on it. However, I'm pretty sure I don't hold it "right". It is mostly (perhaps only?) felt when doing power chords - I think I support my hand with the thumb incorrectly... Any proper videos/explanations on how to hold it right? the RS tutorials are abit... weak...