TPIs are non-surgical procedures for pain that only takes a few minutes to complete in the office. Trigger points are small, tender knots that can form in muscles or the fascia (the soft, stretchy connective tissue that surrounds muscles and organs). Many times, such knots can be felt under the skin. Trigger points may irritate the nerves around them and cause referred pain, or pain that is felt in another part of the body. A combination of a local anesthetic and steroid are most commonly used.