I have a 2002 Explorer XLT and when i am coming to a stop or taking off i keep getting clicking sound from my rear passenger side. Does anyone know what could be causing this???

Does your Explorer have rear air conditioning? If yes do you get the clicking with the A/C on? If yes, the problem is likely the blend door in the rear A/C unit. It's a job for the shop. A/C needs to be discharged and the whole assembly which is on the driver's side needs to come out. Listen carefully to figure where the clicking noise is coming from. My guess it's the left (driver's) side.