Pain below rib cage while inhaling.

See your doctor: If it hurts when you press on it. It is likely musculoskeletal in origin and may be a muscle strain. If you had a viral infection recently it could be pleurisy or inflammation of your lung lining. If you are tall and skinny, you may have burst a an air filled sac on your lungs. You could have also pulled a muscle doing strenuous sex. You may need a chest x-ray. You should also do testicular exam

Rib cage pain: when inhaling means you have some inflammation in the tissues around the rib structure. It's a condition called Costochondritis.