​Physical therapists use dry needling to release trigger points in order to relieve pain and increase range of motion. Trigger points are local areas of muscle contracture that can cause local or referred pain, restrict range of motion, and disrupt function. By addressing these trigger points, dry needling decreases pain, decreases muscle tension, and normalizes nerve impulses transmitted to the muscles. Dry needling is a safe and effective approach that aids in speeding up the return to active rehabilitation.
 

Sources:

choosept.com
https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/on-pins-and-needles-just-what-is-dry-needling