Help with Data matching

I’m looking for some assistance with some VBA Code. I’ve just started out with VBA so if this is a silly question please be kind.

At any rate, I’m looking for the BEST way to parse through an array of data from the top down to match a string value with the next closest one down the list so that I can determine the time between sales. Any help is greatly appreciated….

Example
Prouct1 Date
Prouct2 Date
Prouct1 Date

NOTE: Product column has multiple products lists so I can't just go one after the other, I need intelligence to find the next match down the list....