finding chains in a Multiarray?

God Im stuck total mental block

I have an array

Dim Grid(10,10)

this contains values between 1 and 9

I am desperate need of a function to find the largest horizonal and vertical chains of identical values
and have it output the Number of chains and each ones size
for animation and scores
when a chain have been found I want to set all value involved to 10

any ideas would be welcome