I have some white moist, thick stuff under my foreskin it gets removed easily by cloth its grainy and moist, n my belly button also develops some fungi in it so i wonder do i have yeast infection?

This sounds normal. The material under your foreskin is called smegma; the same can occur in any closed space without access to air, like a deep navel. Uncircumcised adults males need to retract the foreskin and wash with soap and water once a day, to keep smegma to a minimum and reduce the chance of infection. Presence of fungi is not abnormal unless there is inflammation (redness, irritation).