How can I make my headphone jack work on my Macbook Pro 15" Retina Display, it quit working randomly So I have been using different headphones here and there, but also running a synthesizer program out of my headphone jack into the mixer for live audio performance. 

Everything always works fine, except for yesterday, it started that no headphones/speakers will work anymore for anything coming out of the 1/8" headphone jack.  Yes, I have them plugged in all the way, yes i have tried different headphones/speakers etc...  Yes I have gone into settings/audio and selected the proper output and made sure that nothing is muted, all sound is balanced and that it is turned up.  The headphones just put out the most faint level of audio that isn't easily detected unless you really press the headphones onto your ears.  All this while the regular Macbook speakers work if you unplug the headphones.  

I need my headphones to plug in so I can mix audio that has to be done this week, yet I can't get any sound through them.  I have tried all things online to reset certain functions of the computer, and the closest Apple store is over 2.5 hours away.  What makes this situation worse is that I have Apple support by phone but I am unable to speak due to strained vocal cords, so I am kind of in Limbo, is there anywhere to chat online?
Your speakers not working after you unplug your headphone jack is a dead giveaway that your headphone jack is full of dust or some other kind of foreign substance. Get a can of compressed air (you must be 18 to purchase compressed air, also it costs about $5 per can) from Wal-Mart or Best Buy or another retailer and use it to blow the headphone jack clean and you should find that it works again.