I am 20;110kg 6ft male.i hv dvlopd knee pain recntly, i strts to hrt aftr wlkin mr thn a km at strech.i can't exrcis as it pains, please help me lose wt.

See details: Minimize carbohydrates (no bread pasta, sweets, fast or junk food, etc) and control portion size. See a doctor to determine the cause of your knee pain and then treat that cause.

Probably instability: Probably related to joint instability. Exercises to strengthen quadriceps muscles and assuring good foot mechanics generally helps. Correct the instability and you will likely be able to exercise.