Hi.. Welcome to HEALTHCARE MAGIC... I have gone through your query and can understand your concern.... As per your complain hurting of jaw on opening can be most probably due to displaced articular disk which is a soft cushion present between two ends of bony joint and if it gets displaced then on opening mouth after a certain limit leads to pain and there is restriction in opening mouth.. This can happen in case if there is trauma to the jaw joint or there is excess opening of mouth during some dental procedures, laughing, yawning etc.. You should consult an Oral Surgeon or an Oral Physician and get evaluated and he can take a full mouth x Ray known as OPG and rule out the exact cause of the pain and treat accordingly.. A home exercise progam is available that can be demonstrated to you by your oral surgeon which can help you in improving the painless mouth opening as well as replace the articular disc in position.. Ionotropic chemotherapy is a procedure done to deliver the steroids and anaesthetic agents directly into the region of the jaw joint.. At last when nothing works surgical approach can be made.. Hope this information helps.. If you find the answer helpful please give me a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..