A muscle cramp during pregnancy may occur in any muscle or muscle group, but is most commonly experienced in the legs. Muscle spasms that occur in the back or abdomen are also possible. A muscle cramp or spasm is characterized by the following: 1  Involuntary contraction or tightening of a muscle. 2  Usually sudden.
During breathing, these muscles normally tighten and pull the rib cage up. Your chest expands and the lungs fill with air. Intercostal retractions are due to reduced air pressure inside your chest. This can happen if the upper airway (trachea) or small airways of the lungs (bronchioles) become partially blocked.
Since the intercostal muscles located between the ribs facilitate the movement of rib cage during breathing, a person suffering from inflamed intercostal muscles is most likely to experience labored breathing or painful breathing. The pain may exacerbate with exertion and may also worsen while sneezing or coughing.ince the intercostal muscles located between the ribs facilitate the movement of rib cage during breathing, a person suffering from inflamed intercostal muscles is most likely to experience labored breathing or painful breathing. The pain may exacerbate with exertion and may also worsen while sneezing or coughing.