The oblique muscles are often thought of as the waist muscles. They contribute to pain on your side in the rib cage and waist area, lower abdomen, groin, and pelvis. They can also contribute to heartburn, indigestion, bladder pain and incontinence, and testicle pain.
The pectoralis major contributes to pain in the chest, shoulder, breast and upper back. Pain can also travel down the inner arm, elbow and extend to the hand and last two fingers.
The serratus posterior inferior muscle contributes to pain in the lower back between the bottom of the ribs and the top of the hip. Pain is increased when you twist the torso, bend over, and stretch to reach overhead.
The intercostal muscles are found between the ribs. The muscles can contribute to pain in and around the rib cage. They are also a major contributor to pain in the sides and in between the ribs known as a side stitch.
The rectus abdominis contributes to pain in the area around the sternum, across the upper back, across the buttocks, the lower abdomen, the pelvis. and testicles. It can also contribute to heartburn, indigestion, feeling bloated as well as mimicking urinary tract infection pain.
The diaphragm is a muscle found under the lower ribs. It can contribute to breathing problems, pain in the chest, ribs, and can cause sharp pain in the side known as side stitches.