Gav,
Yes, we should normally be able to return to running after resurfacing, and two years should be a very safe time frame. However, one thing that my surgeon repeated a number of times is that I will always need to build slowly back to any new activity, or even just returning to an activity after a break. I have found this to be true as I return to seasonal sports like tennis and skiing each year. You mentioned spending 30 minutes on the treadmill, but I am not sure if that is something that you have gradually built up to over time. From my doctor's advice, I would have needed to start out at about 5 minutes or less the first few times, and then build up slowly as my body allowed.
I started running at about six months, but I was very conservative in my approach. I ran only on dirt trails (preferably uphill) or sand (treadmills were too much impact for me), so there was very little impact. I would run for a couple of hundred yards, then walk for awhile, etc. If I felt any discomfort at all, I would walk for the balance of the trail.
Hopefully by now your pain was gone away, and maybe you can build back while carefully monitoring it so that you do not get a big flare up again.
Good luck.
John