Tension in the body = tension in the voice (and tension in the voice can lead to ‘vocal fry’ or more serious damage)
The next time you go to sing, be aware of your body- are you standing or sitting with relaxed but solid spinal alignment? Is your neck and face relaxed and aligned? Try massaging your face while you sing to make sure that there is no tension there. Notice if it feels like you are “holding” or tight anywhere in your body. Look in the mirror and sing: How is your head aligned? Do you jut out your chin or tilt your neck when you sing? When your body is aligned you’ll find that you don’t tire as easily, and your voice will be more free and flexible.
Go ahead and ask for that massage- your voice will thank you!