Jersey Shore's Pauly D Working Against Himself

Pauly's "Dirty Couture Shore Store" opened for business yesterday on the boardwalk in Seaside Heights -- but the "Jersey" star couldn't help promote the big day ... because according to his contract with MTV, he's locked in to work exclusively at the infamous "Shore Store" t-shirt shop nearby.

Sources close to production tell us, MTV controls EVERYTHING while the cast is filming -- and Pauly has no choice but to work with his roommates while they shoot the rest of Season 5 ... in enemy territory.