helloo...read thru ur query....i can say that erruption of wisdom tooth can result in lockjaw(trismus)..it can be due to infection beneath the wisdomtooth(pericoronitis).but it is natural...u have to do hydrogenperoxide mouthrinse twice daily...meet an oral surgeon get antibiotics and analgesics...do salt water gargle as many times as poosible..after infection based on amount of space(based on xray).if less space left extraction is required or otherwise it might errupt properly..meet an oral surgeon get the treatment done...hope ur benefitted something from this reply..have a healthy day!!!

Thanks for your query, I have gone through your query.
The difficulty in mouth opening or locking of jaws could be because of the disc displacement in the TMJ. Consult a oral physician and get it examined, you need to take radiograph like OPG and MRI to rule out the impacted wisdom tooth and the disc status respectively.
This can occur secondary to stress, trauma to the joint(bruxism) or malocclusion or secondary to impacted tooth. Mean while 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 there is impacted tooth, you have to get it removed. If you have bruxism, you have use soft splints. Lead a stress free life.
I hope my answer will help you, take care.