In reply to innesmac:
Try making sure your leg loops are not too tight, ie, they hang down at the back somewhat. When you sit in the harness lift your knees. Then, instead of the leg loops pulling into your groin they stay under the back of your thigh, causing your legs to make a right angle with your body and all your weight is supported on the back of your upper thighs, not in your groin.
Regularly see overtight leg loops, and/or legs straight down during lowering and all seem to find it painful. Harnesses used to be called sit harnesses, as that is how they are most comfortable.
P.s if you get large lumps in the side of your neck, the loops are really really too tight!