Amir Khan

Boxing superstar Amir Khan has a message for Floyd Mayweather -- STOP BEING A CHICKEN AND FIGHT ME!!! Khan -- who was in L.A. to see the Danny Garcia fight -- tells TMZ Sports Floyd's been ducking him like a chump ... and it's all because Mayweather's afraid of taking his first L. "It seems to me…

Boxer Amir Khan has landed in Pakistan -- where he's got a heavily armed security escort -- and plans to help rebuild the school that was terrorized by the Taliban. Khan -- who has family in Pakistan -- was deeply affected by the massacre ... in which Taliban militants stormed a school and…