Song stopping where it should not

Hi Bex3697,

Thanks for visiting Apple Support Communities.

If songs you play on your iPhone are being skipped, first see if this article applies to the situation:

iPhone and iPod touch: Songs or other audio content are skipped during playback

http://support.apple.com/kb/TS3159

If one song skips every time or does not play completely, you can delete the file and download it again using these steps:

Before you delete, find out if you'll be able to download the song you deleted again (it depends on where you live). To delete a song:

1. Tap the Music app.
2. Tap the Songs category.
3. Swipe left to right over the song you want to delete.
4. Tap Delete.

From:
How to delete content you've downloaded from the iTunes Store, App Store, iBooks Store, or Mac App Store
http://support.apple.com/kb/HT5772

1. Tap Settings > Music and make sure Show All Music is on.
2. Tap the Music app.
3. Find the item that you want to download.
   
4. Tap the Download icon.

From:

Downloading past purchases from the App Store, iBookstore, and iTunes Store

http://support.apple.com/kb/HT2519

If the behavior continues, I recommend the troubleshooting steps in this article:

iPhone: No sound or distorted sound from speaker

http://support.apple.com/kb/ts5180

All the best,

Jeremy