(Original post by Jessaay!)
As for pace, when I was quite a lot younger I used to do a lot of sprinting, and I have been told I'm quite good at it even now though I don't really do it anymore, so I think maybe my pace may be a little too inconsistent, as when I run at what feels like a natural pace I'm sprinting and definitely can't keep it up, when I'm running slower any technique probably completely collapses and I have to be conscious all the time to keep the pace lower so it probably ends up quite inconsistent.
With cycling and rowing you have props to aid your movement, so to some degree you're always going to have some momentum even if you cease pedalling/rowing. When you stop pedalling the bike doesn't suddenly come to a halt, but will still keep going and can still travel at quite a speed if you're on a hill.
With running it is entirely down to you, you propel yourself forward, and you keep yourself going, which imo makes it more difficult.
It can often be quite demotivating initially and progression can seem very slow, but don't expect to be able to run far to start with, and don't be worried about having to stop and walk.
It might be a good idea to jog/walk 1/2- 1 mile, so jog for 2 mins, walk for 2 mins, jog again etc. until you've covered the distance. Then either try to extend the distance covered with the jog/walk method, or try to run the same distance with fewer/no walk breaks. Eventually it does become easier, and then you'll be able to actually enjoy it!
Do you warm up properly? Try a 5 mins brisk walk before jogging.
Also, you've mentioned your pace and it sounds like you are running too fast to enable you to maintain that pace. Basically, the slower your pace, the further distance this can be maintained.
When racing it is common to run the first mile at a slower pace than the last, and as a general rule every second too fast at the start will add an extra 3-4 secs onto the overall time. So it's important to pace yourself whatever your level of running.
If you're serious about wanting to run then try following a beginner's guide, and as you're already fit I think you may be surprised at how much progress you'll make in a month or so. If you persevere..
It's very rewarding so I highly recommend getting into running!