Suddenly Since Two Days I'm Feeling An Acute Sprain In

Suddenly since two days i'm feeling an acute sprain in my front neck along the longitudinal line of trachea, i'm unable to make my chin up . but movement of my head in all other directions are absolutely normal,only looking at celing is restricted. feeling like a spasm in my neck ,but no difficulties inside the throat like swallowing or any talking or shouting or eating .inside s absolutely normal ,why is it so ..? plz suggest.. taking Signoflam is helping for a certain time then again regain the pain after few hours ..