Brief Answer: Can be due to many causes. Detailed Answer: Hello, Thanks for trusting us with your health concern. The pain in the left lower jaw and soreness in side the mouth and gums can be due to TMJ; a sinus infection; a toothache; arthritis; muscular pain; ear infection or a serious cause like heart attack. If moving your jaw around (such as while chewing) increases the pain, it’s likely the discomfort has nothing to do with your heart. It can be arthritis or muscular pain. Jaw pain that happens in the morning can be an instance of referred pain and serves as a warning sign that you’re at risk for a heart attack. Your blood is thicker at this time of the day, which causes blood pressure to surge, increasing heart attack risk. In case the pain is not relieved with mild pain killers like ibuprofen then a direct examination and investigations are needed for proper diagnosis. Please feel free to discuss further. I will be glad to answer the follow up queries that you have. Wishing you good health. Regards. Dr. Rakhi Tayal. For future query, you can directly approach me through my profile URL http://bit.ly/Dr-Rakhi-Tayal

---