Samsung Image Is Concave On the Sides

About 3 months ago my Samsung Direct-View started flaking out. After it is on for about an hour the image swells and the sides bend in. Even worse...the fix is to bang on the TV slightly or stomp on the floor. It may hold for a bit, but then goes back.

Is my tube going out? How much would that be to repair?

Thanks for any help...

For what that may cost to repair, it might be worth looking into a replacement.