4 Year old walking/running flat footed

[house10]

My 4 year old has started school this week and after school enjoys playing with the other children in the playground. When watching him run we've noticed that he runs oddly. He seems to run flat footed, take really small steps and leans forward. He has quite narrow feet but I haven't noticed that his feet are especially flat.

Recently he's also started to complain that his knees hurt. Initially we'd put it down to growing pains but now wondering if it is all linked?

Does this sound like it's just his way or that maybe we need to investigate a bit more?

My son is flat footed, despite his feet not really looking flat.
You need to observe him without his shoes on really to get a better idea.
I could see that DS's ankles were not properly aligned so took him to the gp who agreed something is not quite right. We have a Physio appt next month and I expect he will probably need orthotics.
If I were you I would get it checked out as flat feet can be really painful. I have them too!