Ideally it is caused by the fall, there is a theory behind it. Severe vomiting
is caused inflammation of pleura, that is outer layer of the lungs. it might be even caused by trauma, inflammation or infection. So severe pleural inflammation
caused severe chest pain
Even it might mimic flu
like symptoms, So what I suggest for you is to get one chest x ray
done and review.
Secondly see if you symptoms do get better with positional variations, like sitting, standing and lying. If it do happens then you might need to under go some more investigations like CT thorax.