Rodd,
IF you are doing it right, there should be no pain and no calluses! The elbow is one reason for this to happen but there are others. You should experiment with a completely relaxed string forearm and wrist. IF you are relaxed there, the string of the bow will align your fingers to a straighter position. Also, don't place the string on your finger tips, put it into the first joint of the fingers (deep hook). You might want to take a look at a video I did a while back called "release tips." You can find the video by going to You Tube and doing a search for "TheMoebow1" See if that gives you any help.
Arne