So here's my story. I bought the LG VX 9400 last September, and I've had no complaints.

The phone has never acted strange on me until this week. Ever since I bought it, I've kept it in my pocket. There has been no water damage, and I've only dropped it a few times. However, a couple of days ago I took it out of my pocket and it was off. I didn't think anything of it, I figured I just accidentally pressed the off button. So I turned it on and put it in my backpack and walked to class. The next time I took it out, it was off again. So I brought it back to my room and turned it on again. I left it on my desk and walked to my friends' room down the hall. Upon returning, the phone was off AGAIN.
This is when I knew that something was potentially wrong with my phone. I turned it on and plugged it into my charger. I use my phone as my alarm clock, so it is on 24/7. When I woke up in the morning, the phone was (thankfully) on. This led me to believe that the problem was with the battery. However, in the previous cases when I would turn my phone on again, the battery life was still 100%.
Does anyone have any insight as far as what could be happening? Is the battery loose (ie losing connection to the phone)? One thing that I noticed was that the closing music that occurs when my phone is turned off was NOT happening, so that led me to believe that it is dying/something is wrong with the battery connection.
Again, any insight would be great!
Cheers