The location “upper left back” could mean near the shoulder blade or could mean the top of the lower back area (thoracolumbar junction or where the chest meets the lower back).
Tingling sensations typically are from irritation to a sensory nerve. If this area is near the puncture site of the epidural catheter, the symptoms could be a result of irritation to the local sensory nerve that exits out of the spine at that level (the medial branch of the posterior nerve).
If this is the case, these symptoms are nothing to worry about. Over time (three to six months) the symptoms should diminish.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.