Why do you think professional athletes spend so much time on perfecting their techniques? Not only to get better results, but also to avoid injury. And even then they don't last very long.
Hell, your arms can even get ****ed up from using a mouse and keyboard.(this in combination with playing guitar is no good at all)
How to hold your pick? However you prefer. I think between thumb and index is the most used way.
Anyway, changing technique isn't that big of a deal. It's easy. The human mind is very flexable, and can get used to change very easily. Humans just do whatever is most easy.
