X Marks the Spot: 3 Hidden Muscle Knots That May Be Limiting Your Shoulder Mobility Lat Trigger points Shoulder pain when reaching overhead? Tightness when lifting your arm? Difficulty reaching behind your back? The problem might not be coming from your shoulder at all. When people experience shoulder pain or limited range of motion, they often focus on the rotator cuff, shoulder joint, or upper trapezius muscles. But there's another powerful muscle that frequently gets overl