Welcome to Beyond Blue and well done for reaching out.
I know for me that when I am feeling anxious, I tend to grind my teeth a lot, and yeah, that can cause some jaw pain and even headaches if I am grinding my teeth quite hard.
One of the most helpful tools I have found over the years is using meditation and relaxation techniques. focus on slowing your breathing down; in through your nose for a count of four, and then out through your mouth for a count of 6. Make sure the out breath is longer than the in breath, because that is what helps to release the tension.
Another thing that I have found helps me to stop grinding my teeth so much, is that as soon as I realise I am doing it, I place my tongue between my top and bottom teeth ..... because one thing I DON'T want to do is bite my tongue, so I tell myself that when I am grinding, I am (in theory) 'biting' myself .... and that's not healthy! Maybe that sounds a bit weird, but it works for me!
Of course, perhaps it may also pay to see your doctor and/or a dentist, just to make sure that things are okay in a physical health sense. And maybe you could also consider talking to a counselor about the childhood bullying stuff? Do you think that might help?
In the meantime you can keep coming back here as much as you like. After all, that's what we are here for.
Anyway, hope that helps at least a little?