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.
Billy's spokesperson Lissa Druss Christman, of Serafin & Associates, says "As president, Billy is looking out for the long-term interest of the company, its employees, its talent, as well as its stakeholders and contractors."
It's a huge falling out ... considering just a few months ago, Corgan was named President of the company and was praised by Carter as a "visionary" and a "savvy businessman."
We reached out to TNA for comment -- so far, no word back.