Jersey Shore

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.

As TMZ first reported, Pauly was one of only three cast members not sequestered at the "Jersey Shore" house in Seaside Heights, NJ -- he was allowed to skip out so he could work this gig.

Winner.

Although some big wigs on the show denied it last week, we're told MTV wants a fresh cast of characters after they wrap Season 5 -- which begins shooting in New Jersey Monday.

Sources connected with the show tell TMZ ... producers want to keep the cast "in the zone" after coming back from Italy. Translation: If they started circulating again in New Jersey with friends, family, and the media, they'd lose the chemistry that makes the show work, and it takes time to get it back.

So given that Season 5 starts shooting on Monday, we're told producers felt it was better to just keep them away from everyone.

But there are always exceptions to the rule. Sammi, Deena, and Pauly D had prior engagements they had booked that could not be canceled -- the girls had commercial shoots and Pauly had a DJ gig in Vegas.

Plans are already in motion for a fifth season back in Seaside Heights -- but sources connected with the "Jersey" cast tell TMZ ... Pauly D, Snooki, The Situation and the rest of the gang refused to take part without signing new contracts first.

We're told MTV originally planned to shoot the new season under the terms of the Season 4 contracts -- but lawyers for the cast refused ... so MTV drew up new papers.

We're told the majority of the cast has already re-signed for a bump in salary -- not a HUGE raise, but still significant -- and the rest will sign this week.

Sources close to Frank Sorrentino tell TMZ, he recently switched to a new brand of meds because he couldn't afford the old one -- and began to experience side effects ... like extremely high blood pressure.

Frank ended up in the emergency room at Boca Raton hospital Tuesday morning -- and was in and out of the hospital for the next few days.

According to our sources, the cast hasn't been told the plan is to shoot season five right after they are done shooting four -- even though MTV announced it yesterday. We're told 495 Productions will break the news either today or tomorrow.

Our sources say the cast was originally told the next season of the show would shoot in August. As a result, we're told the cast members booked club appearances for July -- and those are HUGE money makers.

According to our sources, the cast will leave Italy in late June and go straight to Seaside Heights -- which is a problem ... since no one packed enough clothing.

MTV announced the season four premiere date of "Jersey Shore" on Friday -- and also their plans to start shooting season five later this month. That season, the cast will be back in their natural habitat of Seaside Heights, NJ.

We spoke with a rep for the New York State Department of Motor Vehicles ... who tells us, "Any accidents that occur in a foreign country do not affect a person’s driver license in New York State.”

As we previously reported, Snooki smashed into the side of a polizia squad car in Florence this weekend. She was taken into custody for questioning ... but not arrested.

Bottom line -- when Snooks returns to U.S. soil ... she'll be allowed to hit the streets again like nothing ever happened.

Snooki was driving when she struck the cop car, but sources connected with the production tell TMZ, "Zero alcohol was involved."

We're told no one was injured.

A witness tells TMZ, Snooki smacked right into the back of the patrol car, wedging her ride between the car and a highway protection wall. The witness says Deena was in the passenger seat at the time of the crash -- and when she tried to exit the car, she had to go through the window ... because the door was blocked by the wall.

Multiple sources close to both "Jersey Shore" stars tell us ... the guys had a long talk after the altercation and "worked out their issues."

We're told the whole fight went down in the first place after Ronnie had returned from a night of clubbing with his GF Sammi. Ronnie was pretty heated over an argument he had with Sammi ... and in his rage, "turned his anger towards Mike."

Sources tell us Ronnie began to talk smack to Sitch -- taking personal shots regarding Sitch's family -- and The Sitch eventually snapped.

The two men fought briefly before it was "quickly broken up" -- and Ronnie then blew off some steam by punching a wall and tearing up his knuckles.

As TMZ reported yesterday, Ronnie beat up The Situation the other day -- leaving Sitch with red marks all over his face and left eye.

The two arrived separately back to their apartment hours ago -- Situation has red marks covering his face around his left eye. Ronnie's knuckles were torn up and bleeding.

Details around the fight are still unclear -- but big surprise ... we're told it all began with a blowout between Ronnie and Sammi.

As TMZ first reported, The Sitch filed a lawsuit against his pops for that crazy website he created, TheConfrontationSite.com, claiming his dad is illegally using his name and likeness.

Frank got served legal papers while he was volunteering at a charity event in Delray Beach, FL -- which we posted a story about earlier this week, so we probably tipped The Situation off to his exact whereabouts.