You're using the harness incorrectly. It's supplosed to be used to augment your package. When you put weight on it you're putting some strange forces through your body. That's what's causing the pain. Either you or your climber need to sack up and actually climb instead of rope hanging.
I get a sharp pains under the lower front rib from time to time when I am climbing harder stuff. Apparently you can irritate the lining of the lung, stress ribs and irritate other vitals when torqueing your body under climbing conditions causing sharp pains. Precordial Catch Syndrome is one that you can get. If it intensifies when you take a deep breath then that may be what it is. Or it could be a rib issue. Stop trying to create women.
