As you told that you have been operated for the TB node in the chest and after taking medication for 2 months you left it and again completed the course for 6 months.
From this I understand that this is TB of lymphe nodes and not the lung and you have to surgically remove the node also. It is common that TB medication
for TB of other part of the body apart from the lung is for long duration and should be stopped only after consultation with your doctor only.
Now the pain in the abdomen can be because of recurrence of this or because of some other thing. I would suggest you to consult your doctor to make the confirmation and have the investigations done and keep monitoring yourself.
Thanks and take care