Smashing Pumpkins frontman Billy Corgan -- the president of TNA Wrestling -- is having a nasty falling out with his boss ... suing the wrestling company and filing for a restraining order against the owner.
It's unclear what went wrong ... but Corgan filed the suit against TNA owner Dixie Carter in Nashville -- and also named Dixie's husband Serg Salias, TNA Wrestling and Impact Ventures as defendants.
Corgan also filed for a temporary restraining order -- which was granted -- but so far, the court has not released the documents detailing the specifics of the order.