This is indicative with problems caused by the convergence amplifiers inside your TV set. There are also resistors that could have failed & it is best to replace both parts.
If you have TV repair experience and want to DIY, you can get the special repair kit to address this specific problem by calling 901-414-2399. They offer support to help you along with the process & for any questions that you may have. The kit is about $65.If you do not have the confidence to perform the work, then a technician would charge $250-$350 for this repair.