what causes back spasms on the left side
Quick Answer. Some cause of muscle spasms are overuse or exercise of muscles on the left side, dehydration and atherosclerosis, according to MedicineNet. Nervous system disorders such as amyotrophic lateral sclerosis, multiple sclerosis and spinal cord injuries might be a cause of muscle spasms in various parts of the body. Hemifacial spasms are a specific type of spasm that occurs in the face and most often on the left side, notes the Dystonia Society.