Jones - don't give up just yet.
Couple of questions - what's your route like (flat, hills), how far do you go if you do the 28 mins and can you get out any more often? You probably are still going a bit fast especially if you have stitch. Do you run by yourself, do you have an MP3 player?
Personally I didn't start with a timed run/walk thing, although that's what is generally recommended. I don't really get on with them.
I measured out a cirular mile route from home and just plugged away until I could jog (note jog not run) all the way. It took ages and I was going out 4 times a week. The pace was barely above a fast walk - just that point where you break into a jog from a walk. I didn't time running/walking just ran until I couldn't go any further, walked a little bit then started jogging again.
Once I could do the whole distance at a steady jog I just increased the distance a little (sometimes a very little, even going 50 metres past the end of the drive and back again) at a time but from that point always ran.
Everyone is different and you need to find what suits you. I believe that some people are born runners and others have to work that bit harder. I have a friend who runs with me very occasionally - even after 3 months off she can still go further and faster than me - it's a bit demoralising I know. My other running partner is slower than me, more of a plodder, but she can keep going when I'm on my knees. You just need to find a pace and distance to suit.
You'll get there (wherever there is....)