I have found that it is often dust in the port that makes them feel loose. Cleaning them with a little brush (like the ones that come with an electric shaver) made a lot of difference for me.
The port on my phone started to feel loose to the point where charging became an issue. The dust and lint was compressed so much that nothing short of a steel needle helped.
You can get a small magnetic adapter that plugs into the port, then a corresponding charging lead with a magnet on the end connects to that. This is easier to plug in while not looking (e.g. driving) and has the side effect that the port doesn't fill up with lint since it has the magnetic plug thing in it all the time.