When can I start running again?

[Deleted User]

I started a C25K program, and got halfway through week 4 with no trouble. But towards the end of my run last Sunday I got a pain in my left knee, above and to the left of the kneecap. I then walked to and from the train station to drop someone off, which is probably a mile or two of walking, and on the way back my knee was extremely painful. The next day I again ended up going to meet someone and doing more walking, resulting in more pain, but less than the Sunday. I haven't been for a run since, or done much walking. However it is still slightly painful when going up lots of stairs or being on my feet for prolonged amounts of time.

I was wondering when I would be able to start running again, as I was really enjoying the program and feeling the benefits. Do I need to wait for it to heal completely or could I try to run through minimal pain?

Sorry for the length of this, just wanted to put the detail and explain myself properly.

Any advice on this would be appreciated.

Thanks.