Recently diagnosed w/ strep throat, antibiotics given but not work. Not strep throat, what is it? Sore throat and chills, feverish, chest pain, cough.

Viral. There are a number of viruses that can be causing this. Hand, foot, and mouth disease is possible. You should be checked for monomucleosis also.
Sounds viral. This sounds like a viral illness. This should resolve, but if not, sometimes a viral illness can reduce the immune system, and a subsequent bacterial infection may develop.