After researching I found that the Original EVO had a faulty headphone jack issue. So when my Shift would cut out I assumed the jack was to blame. I had the issue on two occasions.
1st time) I found I had lint in the jack, tweezers fixed that issue.
2nd time) Jack was clean, but the actual headphone plug would pop out ever so slightly anytime it was moved gently (i.e the phone shifts in your pocket).
I assumed this was to do with the pins in the headphone jack wearing down\being pushed back and not always returning back and locking with the connector on the headphone. This definitely would be an issue for most Shift users over time (users who use headphones a lot at least.) Now after searching the googlez' I didn't see that many hits on people having issues with their shifts headphone jack, only one or two posts on xda & android central about how "touchy" the jack is (i.e headphone would pop out a TINY bit, it's normal to have this kind of play, my her did as well, with no issues). So instead I looked at my headphones themselves (their connector), gathered 4 pairs and tried them all. 3 of them are pretty pricey, and their connector would pop out of the phone ever so slightly when moved, the 4th pair (cheap ear buds) had no problem whatsoever . So what was the difference? The LENGTH of the gold\silver connector. I lined them up side by side under a light, and lo and behold, the 4th cheap one was slight shorter, and it allowed it to sit snugly and "snap" into the phone, and would not pop out under movement, the other 3 pairs were ever so slightly longer. So my solution? Metal nail file, and take down a little bit of the tip, which lets the plug sit all the way in. Be careful not do damage your connector on your headphones. Or you could just buy another pair and make sure it's not too long (the connector tip). Hope this helps some of you folk out there.