Give it some time and see if it improves. It's impossible for me to diagnose this aspect of playing with email, my embouchure training routine would certainly be worth looking at. If you can give me more information about your location in Australia I might be able to recommend a teacher. If you're finding no improvement it would probably be best to take a few lessons with a local teacher to see if there's something fundmentally incorrect about your embouchure causing you pain. The most common factors for this would be too soft a reed.
Many teachers recommend a soft reed and closed mouthpiece for first year players.
This alone causes the pitch to be flat. The reed does not support the pitch. It seems I really grab at the horn. This probably stems from years of worrying about squeaks, etc, etc but it seems difficult to break this and get relaxed and fluid in this transition. You have already begun to solve the problem by noticing the tension.