You are describing a problem that is quite common for beginning sax players. The best thing would be to find a good private teacher to help with your embouchure, breath support, and choosing the right reeds and mouthpiece. That said here are a few ideas that might help. Push in more at the corners of the mouth when you play. Think of the embouchure as a tug o war between the ee muscles pulling out and the oo muscles pushing in with the oo muscles winning the contest. Do the smile - whistle - smile - whistle 50 times exercise twice a day to build up the embouchure muscles. Develop the feeling of the jaw and lower teeth pulling down and away from the reed when you play---not pushing up against it. To help develop this feeling of pulling down, press down more with the top teeth on the mouthpiece, push forward slightly with the thumb in the thumbhook, and imagine blowing your airstream toward the thumb on the octave key. Play long tones every day to strengthen the embouchure muscles and be careful not to use reeds that are too stiff as that will encourage biting. Good luck. Hope some of this helps. John