There are many muscles in your throat, connecting your tongue, jaws, larynx and your scull with each other. When there is too much tension you will have difficulty making the voice sounds free.
Too much tension also prevents your larynx from tilting.
A good way to relax your throat, jaw and tongue is to do the ‘Larynx Shuffle':
Fold your hands, like in prayer, and start moving your folded hands up and down. Do this with a lot of energy and pretty fast! You will feel your throat and lower jaw loosen.
While shaking your hands, start to make sound, do a vocal exercise or sing a song (without words). Sing both high and low notes.
This exercise wil help you to release tension and will wake up your voice.