Nykyria :
If you have cleaned the jack (The part you plug your headphones into) and cleaned the plug (end of your headphones) and it still does it with ALL headphones, then it is more than likely the jack itself may have a bad spot. (I'm assuming you are using the front headphone jack on your computer and as you didn't specify laptop/desktop/front or rear jacks I have no idea how many jacks you may have. If your on a desktop you should also try the headphone jacks on the back of the computer (You may have more than one if you have a separate sound card) and see if it does the same things as the front jack. If you plug into the sound card (A sound card will have a seperate headphone jack from the motherboard), and you get the same thing, you may want to try (Turn computer off for this) opening your computer and removing the card that you plugged into and blow the connector out with canned air and reinstall the card and try again. If you plug into the mobo and it does the same, the sound chip could be going bad on the mobo. If it is only the one jack, you can purchase a new headphone/mike/speaker jack inset for your computer as they are pretty cheep and easy to install as they should plug straight onto the mobo with a usb. For a laptop, I have no idea and good luck.
Sadly, that's not the case. I have, headphones... That won't work unless, i move it or, get it off my lap. But, there are only one plugin hole for the headphones end, to connect too. Specially, for me i have never clean my computer unless, i have spilled jam, or jelly or any sticky goo on it. (But there, are probably more than 1 plugin hole maybe on desktops, like office desktops, or laptops. But my mac, and windows as only "1". And, unfortunately for me the windows "Plugin hole" broke so, now i have my mac to depend on, and my head sets were working perfectly fine. Until, this exact moment.....
i guess, well in good i have to wake up tomorrow and buy cheap head-sets. :/