You may have a dominant side, that side to which you incline when you sing or to which your head is drawn on high notes.That might not be so bad, but it may be worth investigating. When you stand to sing, is your weight evenly delivered to the ground? Is one foot bearing more weight than the other? If it is hard to tell, stand with your feet 12-16 inches apart, more or less, toes pointed slightly outward, and shift your weight from one foot to the other. Stay on each leg a while and notice your comfort level. You may find you’re well balanced. Good! If you do find a dominant side, stand equally footed, and let the leg and foot of your non-dominant side shift somewhat back, more or less so as you experiment. When you find a comfortable place for your nondominant foot, shift all your weight there until you can paw the earth with your dominant side foot. Now, gradually bring part of your weight back to the dominant foot, until the weight is more or less equally distributed. Try singing from this new standpoint. It may seem quite strange, and it may disturb your singing. Let it be for a while and observe. Breaking a life-long habit may prove deeply uncomfortable, but comfort in habit is always worth taking a hard look. Equal footing is a mandate.