When a werewolf transforms is it painful?

According to most literature – and most films – transmogrification (which means to change or alter greatly – in other words the process when a werewolf transforms or shapeshifts), is a painful process.  Most literature and films depict the transformation process as painful, and that is what is used to justify the fact that the werewolf is vengeful, angry, merciless, and vicious.

However, contrary to what is depicted by authors and directors, I have heard that this is not correct, and really the only painful transformation for a werewolf is the first one. After the very first transformations, the body and mind start to become accustomed to the process, and it becomes second nature, and not really too painful at all.