Re: Pain in aikido?
Pain should not be the goal of practice, but it is, and should be, one of the consequences of the learning process. Unless we are talking about the "fluffy bunny" approach to Aikido, it is, and hopefully will remain, a martial art. You can't learn to swim without getting wet, you can't learn MA without some knocks and bruises. Of course it should be tempered according to age and health, and there should never be intentional misuse of the uke/tori contract, but at the same time if there is never any pain how can you learn to work with and around your physiological responses. Immobilizations do hurt somewhat, and hurt a lot if uke is resistant, or tori is insensitive, but they do not work solely on kuzushi, unless your uke has already planned to surrender their balance before completing the attack. Rather like atemi, an empty gesture unless the capacity to actually strike has been developed, so too is an immobilizing technique that does not contain the power and accuracy to do serious damage if taken further than uke's natural flexibility and bodily alignments.
I'm old fashioned, I still believe that experiencing graduated pain (and sometimes real fear!) are part of the martial path and without these two aspects at times being present you may as well do dancing, (By the way, even dancing cause pain when done too hard or too seriously ;-) )