MacBook Pro 15" 2011 Audio Output Problems

As the title suggests, I'm having some issues with the core audio driver in my 2011 15" MacBook Pro. It will spasmodically change the audio output routing between internal speakers, then to optical out, and then to headphones (in no particular order) as if I were plugging in headphones or an optical cable into the headphone jack. Obviously this is quite annoying when I'm just casually using the computer to watch or listen to something, but when I'm working on any mixing/producing projects, it is downright infuriating. This has been going on for about two weeks on and off, not happening for a few days at a time and then happening for a few days in a row. My guess is that it's just a faulty audio output jack, but since my warranty isn't good anymore, I have absolutely no desire to take it to a mac store to double check. Has anyone ever experienced anything like this? Any thoughts? Thanks in advance!

Have you tried to plug/unplug headphones?
Sometimes it could just be a pin in the headphone jack touching and it makes the problem you're describing happen.

You can use a toothpick or something to rebend them back
Search for red light in the headphone jack. Same concept.

Yes, I've tried moving around the jack with a 1/8" headphone insert and then with a pen cap to no avail. The computer also hiccups when the audio routing changes. For example, if I'm typing or moving my cursor around the screen, everything input-command related locks up for a little less than a second and then resumes, while videos and music continue playing (although the sound doesn't come out of course, since the computer's directing it elsewhere). Another thing to note is that while headphones are plugged in, the problem will sometimes continue to happen.