Is my headphone jack on my iMac broken?

That is a photo inside my headphone jack on my iMac that i bought around 2 weeks ago. Everything has been fine up until this evening when I got home from work and plugged my headphones in to listen to music and the sound kept playing out of the built in speakers. I took the jack out then plugged them back in again and then the music played through just the left headphone. Twisting the jack makes a crackling sound and more often than not stops the music playing through my headphones and outputs it straight to my speakers again. I presume this is a warrantable issue?