thanks for sharing your concern.
your history requires little more clarity. A small fracture
could be suspected as you have mentioned two very important features like a sharp pain
that you experienced and the non union of the teeth in both the arches.
i would suggest you to see your dentist
soon and get an OPG xray done.
this will help you to understand the pathology(could be a hair line fracture), any cyst,tumor
,etc. which is causing pressure on other teeth.
since it lower jaw and if your age group is between 18 to 25 years, then you can suspect an impacted third molar too.
so please confirm it through xray after consulting a dentist.meanwhile take tab combiflam
500 mg every six hourly.
hope it helps.