The sore jaw could definitely be related, yes. TMJD is a not uncommon complication that can tie in with stress/depression. TMJD stands for temperomandibular joint disorder. It can be caused by various things, dental and otherwise. In the case of stress it can often be triggered by grinding your teeth, subconsciously or sometimes even in your sleep.
If you are tense and you are biting down the the muscles in your jaw are going to get tired and sore, that's only natural. You would profit from investing in some relaxation techniques for those times when you are stressed. You might find that some over the counter painkillers provide an element of relief when your jaw is sore but check with a pharmacist as to what is okay for you to take. You might also benefit from the use of a warm or cold compress against the jaw to soothe the discomfort.
If it becomes very troublesome then see a doctor or dental specialist. Various things can be done to relieve jaw pain. If you grind your teeth in your sleep you can be given a mouth guard to wear at night that will stop this happening, for example.