Congrats on your little man and great to see a daddy in here!

The other ladies have made some great suggestions but I have found that unfortunately babies can sometimes be unsettled for no particular reason, or no reason that is obvious to us. I think often they just freak out at everything around them as everything is new, every day they are bombarded with new sights, sounds and smells and it can be very overwhelming for them. At around 4 weeks I found that my little girl could start to focus her eyes on things much better and this resulted in a bit of over stimulation for her. If you think it may be colic or wind then there are some natural remedies that are suitable for little ones, just pop down to your local chemist and ask them for advice, chiro's are also supposed to work wonders for things like this. You could also try some soothing music. You can get CD's of womb like sounds which are very comforting for babies, we have a baby lullaby CD that we play each night to help our little one settle and it definitely does help.

best of luck!