[Frogzlovzy]

how long have you done karate?
and why would you not want to carry on with it? or does it clash with your aiki.
i carried on with judo for quite a while after i was enlightened with iai.
i now do aikido to keep fit, as i cant do kendo anymore.

a lot of people do more than one art, dont quit straight away...or filter out of doing it-e.g, cut down on the amount of training you do.
but the best thing would be to talk to both karate and aiki teachers about your situation.

oh and if it hurts, it means its good for you...honest