The trouble ( apparently ) with airbrushes is the way you hold them. There was another one design by Conopois who were later bought out by Rotring, these are now rarer than rocking horse sh*t, if you can find one they might cure the problem as you hold them much more like a pen or pencil.
Sorry can't get the youtube tag thing to work correctly ??? Any mods feel free to edit this so it does - ta
http://www.youtube.com/watch?v=yAL5hMtF_vA
I developed massive problems with my arms, pain from shoulder down to finger, nasty. Had loads of tests done which were pretty unpleasant and it seems it was bi-cubital tunnel. Like carpal tunnel but further up the arm. It's your ulner nerve on your elbow, squeezing the spray gun trigger made it worse for me but maybe get a cheap one of those and see if it does the trick ? My friend used to use one called a Calarni
http://www.graphicsdirect.co.uk/prod...mini-spray-gun
They seem a bit spendy though. I've always used Iwata - great airbrushes. Got some copies of them now which are okay but not a patch on the genuine thing !