Just perform one x Ray of front region teeth and consult Dr. whether all teeth need rct or not. U need to perform rct for needed teeth becoz these teeth will lose at age of 7.5- 8 yrs. For remaining teeth simple filling process can be done.
Kindly get an X-ray done of the tooth having pain. May be you will have to get root canal treatment done followed by a cap/crown. Brush your teeth twice daily using correct brushing technique to maintain your oral hygiene.
There is no relation of your dental health with ulcerative colitis or Hepatitis B.
Seems like your dental problems are not explained and taken care properly.
You might be having multiple carious teeth which are not taken care at the right time which leads to multiple visits.
You should ask your present dentist to do a complete examination of your teeth and oral cavity and explain to you all the treatment that you need. Completing the treatment of all the teeth which require attention. Your job will be to be regular with the follow ups and take care of oral hygiene properly at your home. Once all the potential areas of problems are taken care off and explained to you then you will notice that you are not having any new dental issues. This way there will be no more new dental problems and you can be lead a happy and healthy life.