is a very common presentation of TB. It is good that you are taking anti tubercular treatment regularly for last 4 months. You will have to continue the treatment for at least 2 months more under the supervision of your doctor. As you have shown good improvement with treatment you need not worry and the pain described by you will gradually disappear. This pain is mostlly due to pleural thickening which occurs as a result of healing or mild persisiting pleuritis
which will subside with time and continuing treatment. You should do deep breathing exercises which will minimize the pleural thickening and help your lungs to expand.