Muscle Tightness vs. Injury

A simple way to identify a tight muscle compared to an injury, is that a tight muscle will feel sore (like you had a good workout) and you will still be able to move it with limited range of motion with some discomfort and might be able to get further movement if some else helps you stretch in that direction (passively). Injury on the other hand is actually painful such that almost any motion of the affected area hurts and should be seen by a professional. When in doubt, it is always safer to have a professional check it out before it gets any worse.