The pain could have been because he lied to protect Emma. And I don’t give a crap what the writers said on the podcast, they could say stuff to throw everybody off. That’s what they do.
Protecting Emma was his mission he said himself that he strayed from his mission egardless of what the writers say on the podcast August in show said that he was reaping the consequences of not doing what he was suppose to be doing. Lying to protect Emma or doing something for Emma is still in line with keeping his promise, for him to have been turned back into wood means that he wasn’t acting selflessly or in Emma’s best interest or in the interests of anyone but himself.