Thanks for your query, I have gone through your query. The limited mouth opening and pain could be because of arthritis, the bruxism and trauma leading to disc displacement in the Temporomandibular joint. Consult a oral physician and get it diagnosed. You can take anti inflammatory drugs like piroxicam 20mg twice daily on first day and twice daily on next 6 days. You can also take muscle relaxants like chlorzoxazone. You can give hot fomentation over the joints. Do not eat hard things, do not open your mouth too wide. take soft diet. If it is improved after this, you can get soft splints done. I hope my answer will help you, take care.