Trigger point injections (TPI) may be an option in treating pain for some patients. TPI is a procedure used to treat painful areas of muscle that contain trigger points, or knots of muscle that form when muscles do not relax. Many times, such knots can be felt under the skin. In the TPI procedure, a health care professional inserts a small needle into the patient’s trigger point. With the injection, the trigger point is made inactive and the pain is alleviated. Usually, a brief course of treatment will result in sustained relief. Injections are given in a doctor’s office and usually take just a few minutes.