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 latissimus dorsi is a large flat muscle that covers the mid to lower back. It can contribute to pain in the shoulder, upper back, and arm going down into the hand. The muscle can also cause pain in the side of the ribcage and lower abdomen. The lats can also affect breathing.
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 serratus anterior muscle can contribute to pain down the side of the ribs, around the shoulder blade, and may chest, arm, hand and fingers. It also contributes to pain in the back around the shoulder blade and down the side of the ribs.
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 diaphragm is a muscle found under the lower ribs. It can contribute to breathing problems, pain in the chest and ribs and can cause the sharp pain in the side known as side stitches.
The iliocostalis lumborum muscle is found in the back along the spine. It contributes to pain in the low back, hip, buttocks and occasionally the abdomen.
The longissimus thoracis muscle contributes to a deep aching pain in the lower back, hip and buttocks. Rising from a sitting to a standing position can cause an extreme feeling of stiffness and a deep ache pain.
The iliocostalis thoracis muscle can contribute to pain in the chest, upper back, lower back, and abdomen. Pain tends to be more concentrated around the shoulder blade and / or low back kidney area.