Touch screen issues?

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I'm having issues with my new iPod touch 4g... Its only 3 weeks old.. I was playing street fighter 4 and I noticed that the screen stopes responding correctly.. It gets like stuck for some seconds... I was thinking that it was an issue with the game but I noticed later that actually this happens every time I touch the screen with two fingers at the same time! Do you think it may be something with the jailbreak? Or is the screen? I cleaned it and is still doing it.. Do you know how to fix this?