Hi, As per your complain it seems that you have jaw joint dysfunction leading to the symptoms that you are experiencing of pain during chewing and moving the jaw side to side. The condition is known as TEMPOROMANDIBULAR JOINT DYSFUNCTION commonly known as TMJ/TMD. Locking of the jaw that used to cause difficulty in opening mouth seems to be most probably due to dislocation of the lower jaw that can cause locking of the jaw. As the backward movement of the jaw has become difficult to chew then also there is improper placement of the jaw leading to pain and restricted movement. Consult an Oral Physician and get evaluated and a clinical evaluation and investigations like Panoramic x ray can help in diagnosis and treatment can be done accordingly. As of now you can take anti-inflammatory painkillers like Ibuprofen and muscle relaxant like Tizanidine. Take soft diet. Avoid excessive mouth opening. You should also avoid taking stress as it can aggravate the symptoms and can do yoga and meditation for reducing stress if present. The physician can advise you Physiotherapy along with medication and also mouth guards for improving the condition. Hope this helps. Let me know if I can assist you further. Regards, Dr. Honey Arora