thanks for the query,
from the description that you gave to us, there are chances of some respiratory infection (respiratory tract
or lung infection
), which can be diagnosed by doing some lab investigations like blood examinations and x-ray chest for which you need to see your doctor nearby you.
your back may or may not be associated with your chest infection
for which you need to get an x-ray of the spine as well.
because your back pain
can be related to your chest infection or if it is due to some musculoskeletal problem , it will be clear by the x-ray and will also be supported by your blood tests.
so i would suggest to you to kindly see a doctor nearby you who can guide you with all the tests that you need to undergo. do not delay as you are already in lot of pain.
i hope this answers your query
wish you good health