Thank you for the query.
It is very common that couple of days after trauma the pain is getting worst. It is caused by repairing processes of soft tissues due to nerves irritations by cells degradation products. So you probably are suffering because of soft tissues (muscles, tendons) contusion
. Such pain can last for about a week or two. But such pain can be also caused by some fractures
as well. Left side trauma should be always checked for spleen
It is advisable for you to have left arm and hand, left leg X-rays and abdominal ultrasound
to rule out fractures and abdominal internal contusions.
Hope this will help.