Can u help? the right side of my body, below my armpit, between my 3rd and 4th rib was in a lot of pain. now it hurts when i cough or sleep on my side

Costochondritis..?: Sometime pain in between the ribs may be result of inflammation of tendon , muscles in between ribs. If you right handed - some activity - repetitive motion could trigger it ( as cleaning, workout,.) . Whenever chest & ribs expands as deep breath, cough, sneeze - it hurts because of inflamed area is irritated. Try ice Ibuprofen 600-800 mg every 8 hours with food. Stretch. See doc if no better .