So sorry, but I've not read this entire post, so I apologize if this has been covered. I have had this problem for a while too. It has been getting worse. My problem is only when I unplug from my AUX cord, not my headphones.
So this time, when it happened again, I plugged my headphones (never had a problem with these) in and immediately removed them from the jack & then I had sound.
To me this sounds like a hardware problem with the phone's jack. I called Motorola today about this because I couldn't stand it anymore and after explaining my situation, they acted like they've never heard of this before. Is there anyway to bring this thread to the attention of Motorola, Verizon & Google?
I'll keep checking back with you all for some sort of solution, and I will actually read the entire post.
PS I really didn't have much play in my jack either