Most likely you have a strain in the neck and/or shoulder.  Most likely more so in the neck because it hurts in flexion and extension.  Everything is connected and when you strain the lower neck it will often effect the shoulder on that side.

A fall can be similar to a whiplash injury to the neck.  Muscle massage to the neck as well as the shoulder may help.  Pain may be in the top or front of the shoulder but often the pain comes from the rotator cuff muscles which mainly lie alll around your shoulder blade.  There is most likely knots and muscle tension at the V where your shoulder and neck meet.